Introduction. Red-purple pitahaya (Hylocereus sp.) is a promising crop grown commercially in dry regions of Central America. Both its skin and flesh are characterized by being a glowing, deeply red-purple color. Materials and methods. The main physicochemical characteristics of three commercial cultivars of red pitahaya were assessed, including total phenolic compounds contents, total betacyanins, vitamin C and oxygen radical absorbance capacity (ORAC). Thermal stability of betacyanins at different temperature and pH was also assessed. Results and discussion. Pitahaya fruit has a low vitamin C content ranging from (116 to 171) µg·g–1 of fresh pulp without seeds, but it is rich in betacyanins [(0.32 to 0.41) mg·g–1] and phenolic compounds [(5.6 to 6.8) µmol Eq gallic acid·g–1]; it has a high antioxidant ORAC value of (8.8 to 11.3) µmol Eq Trolox·g–1. Visible spectra of aqueous fruit extracts were very similar to that of pure betacyanin. Indeed, the characteristic color of juice diluted to 1% presents a high hue angle (H° = 350º ± 3) and high chroma values (C* = 79 ± 2). Thermal stability of pitahaya betacyanin decreases with pH, but it remains compatible with industrial utilization as a colorant (half-time = 22.6 min at 90 °C at pH = 5 of the fruit) and was found to be very similar to that previously reported for beetroot. Conclusions. Pitahaya juice combines the functional properties of a natural food colorant with high antioxidant potency.

Introduction. A recent laboratory study demonstrated a negative correlation between the ethylene production of fruit during ripening and the length of their commercial life. The aim of our work was to determine whether there is a putative relationship between ethylene production of fruit during ripening and the length of the growth period before ripening. A positive answer would make this an important parameter for early selection in breeding programs. Materials and Methods. Four banana varieties representing a broad range of growth period lengths were studied. Ethylene biosynthesis was examined through ethylene productionand content in free 1-aminocyclopropane-1-carboxylic acid (ACC)—the immediate precursor of the hormone—during fruit development and ripening. Fruit ripening was totally achieved on the plant. Results. Ethylene production started to be detected at the breaker stage. It peaked at the “fully dark-yellow–extremities included” stage for all varieties. Two varieties, i.e., Sowmuk and IDN 110, presented the highest production levels [(26 and 19) µL ethylene·h–1·kg–1 of fresh weight at peak, respectively). Galéo and Grande Naine had lower ethylene yields. The two most productive varieties also presented a drastic increase in free ACC at ripening onset. Conclusion. There is no relationship between ethylene production of bananas ripened on the plant and the length of the fruit growth period prior to ripening onset.

Introduction. A study was done to compare Gruesa, a local dwarf Cavendish selection, with two other cultivars of the Cavendish subgroup in the open air or under greenhouse conditions in two localities of the Canary Islands. Materials and methods. The trials were set up with the cultivars Zelig, Grande Naine and Gruesa in four plots on the northern slope: one outdoors and three under three different greenhouse covers (one with polyethylene lamina and the other two with different types of mesh), and in one outdoor plot on the southern slope of the island of Tenerife. Morphological, phenological and production characteristics were studied over three productive cycles. Results. Significant differences were found in both plant height (Grande Naine > Zelig > Gruesa) and pseudostem thickness (Gruesa > Grande Naine = Zelig). Each cultivar showed a stable [height:thickness] ratio, remaining the same in all trial conditions. Gruesa cycle length was longer than those of the other two cultivars, emitting more leaves until bunch emergency. Gruesa produced the most hands per bunch and the most fingers per hand. In all cultivars, finger length was directly related to pseudostem height. All three cultivars produced well, with fruits very similar in organoleptic traits. A reduction in cycle length and a slight increase in productivity were observed in the northern plot under the polyethylene cover compared with the plots under other covers and outdoors. Conclusion. Gruesa appears more recommendable than Zelig and Grande Naine for open-air plantations in windy localities.

Introduction. La durée de vie verte (DVV), qui indique l’état physiologique des bananes à la récolte, est un critère de qualité majeur pour l’exportation des fruits. Afin d’évaluer et de comprendre la variabilité de la DVV existant en exploitation, une enquête diagnostic a été menée chez trois producteurs de bananes en Martinique utilisant la méthode des sommes thermiques comme outil de décision de récolte. Matériel et méthodes. Pour chaque producteur, des fruits ont été prélevés en sortie de station d’emballage sur 10 % des régimes récoltés pendant une semaine. Ces bananes ont ensuite été conservées à 14 °C dans des sacs perforés en polyéthylène jusqu’au stade de maturité « tournant vert ». La DVV a été définie par le temps écoulé en jour entre la récolte et ce stade de maturité. Résultats et discussion. La DVV a varié entre (18 et 69) jours avec une moyenne de 42 jours pour l’ensemble des producteurs. Près de 80 % de la production a eu une DVV entre (25 et 50) jours et moins de 4 % en dessous de 25 jours. La variabilité de la DVV a été liée principalement à l’âge des fruits à la récolte, exprimée en somme thermique (R = –0,74). Celle-ci a varié entre (600 et 1150) degrés-jour pour l’ensemble des exploitations. Les fruits contaminés par l’anthracnose de blessure et les pourritures de couronne ont présenté une DVV plus courte que les fruits sains et cela indépendamment du stade de récolte (p < 0,001). L’origine de cette contamination a été discutée. À même somme thermique, des différences significatives de DVV ont été mises en évidence selon le lieu de production (parcelle) (p < 0,001). Des écarts de plus de 7 jours en moyenne ont été observés entre des parcelles provenant du même producteur et situées à même altitude. L’origine de ces différences a également été discutée.

Introduction. La diffusion de nouvelles variétés issues de programmes d’amélioration génétique (hybrides ou introductions) rencontre parfois des difficultés. Pour limiter ce problème, une démarche méthodologique visant à faciliter l’adoption de ces variétés par les planteurs a été mise au point au Cameroun sur un hybride de type plantain. Matériel et méthodes. La démarche entreprise a cherché successivement à hiérarchiser, par enquête, les critères de préférences variétales privilégiés par les producteurs ; à tester, par des essais en conditions réelles, en quoi une nouvelle variété répondait à ces critères ; à évaluer les performances agronomiques de l’hybride et d’une variété témoin en fonction de la diversité des milieux. Résultats. Les résultats ont souligné l’intérêt de l’approche présentée pour comprendre les déterminants d’adoption d’une nouvelle variété par les planteurs. Ils fournissent des informations utiles pour le pilotage de futurs programmes d’amélioration génétique. Ils révèlent des difficultés méthodologiques dans la réalisation d’essais interdisciplinaires en conditions réelles, qui devront être pris en compte pour l’amélioration des protocoles futurs. Conclusion. Les conditions d’adoption d’une nouvelle variété varient selon les localisations, compte tenu des variables pédoclimatiques, et selon les planteurs, compte tenu des contraintes socio-économiques. L’offre variétale doit donc être diversifiée pour répondre à la diversité des demandes. La démarche effectuée gagnerait à être complétée par des enquêtes auprès d’autres opérateurs de la filière. Notre expérimentation doit être considérée comme une première contribution à une démarche plus large.

introduction. Le bananier plantain contribue à la sécurité alimentaire et aux revenus des populations de l’Afrique sub-saharienne. La qualité sanitaire du matériel végétal utilisé en bananeraies est un gage de leur pérennisation. Pour lever cette contrainte, les techniques de multiplication rapide du matériel végétal utilisent des méthodes de multiplication horticole in vivo ou de micropropagation in vitro. La micropropagation par bourgeonnement in vitro, qui permet une production massive de plants de bonne qualité sanitaire, ne fait appel habituellement qu’au bourgeon apical (bap) ou terminal du rejet, alors que celui-ci possède également des bourgeons axillaires (bax) dont nous avons évalué les potentialités. Matériel et méthodes. Nos expérimentations ont porté sur le cultivar Big Ebanga (groupe génomique AAB, sous-groupe des plantains, type faux-corne). Nous avons comparé, au cours de l’acclimatation en ombrière et en champ, les paramètres de croissance et de développement de vitroplants issus des deux types d’explants bax et bap. Des plants issus de rejets ont été utilisés comme témoins. Résultats. Les paramètres mesurés sur les plants issus de bax n’ont pas présenté de différences significatives à la fin de l’acclimatation par rapport aux plants issus des bap, hormis le rapport foliaire. De même, les paramètres de croissance végétative en champ et ceux liés au rendement n’ont pas été significativement différents entre les deux types de plants bax et bap. Les pourcentages de réversion du type « faux corne » vers le type « french » ont été de 0,6 % pour les plants bap et 1,2 % pour plants bax. Discussion et conclusion. Les plants issus de bap et bax se sont comportés de la même manière pendant l’acclimatation en ombrière et en champ. L’utilisation de bax permet d’augmenter les potentialités de production in vitro d’un matériel végétal de qualité. Le taux de réversion des plants bax a été faible. Les bax peuvent donc être utilisés comme explants pour la micropropagation du bananier. Des expérimentations effectuées sur d’autres cultivars appartenant à d’autres groupes génomiques permettront de confirmer ou infirmer ces résultats.

Introduction. In Cameroon, plantain plays a major role in food security. An increase in production is necessary to satisfy the demand. Since April 2002, CARBAP has supported a monitory centre of plantain production. The main objective is to prioritise studies of production constraints and characterise commercialisation strategies, in order to improve profitability for small-scale farmers. Materials and methods. Eighteen plots were identified within farms that represent the agro-ecological and socio-economic diversity of the region. Plots were considered as the sampling unit for agronomic and pathogenic constraints analysis. Farms were considered as the sampling unit used in the socio-economic constraint analysis. For each plot, a regular survey of 50 banana plants and agronomic practices was carried out. A survey of each farm was also set for the observation of production conditions thanks to the participation of smallholders. Results. It is possible to distinguish smallholders with different levels of diversification towards plantain production. Agronomic results in the plots surveyed were judged thanks to parameters of growth, yield and pest infestation. Good/bad results on young/older plots were basically distinguished. These divisions of individuals are influenced by initial factors (varieties available for planting, former crops in the plot), means available (inputs) and technical skills in plantain cultivation. Conclusion. This method allows the detection of indicators of diversification towards plantain cultivation and allows one to check the sustainability of such strategies. It is possible to propose improved technical practices. They will be used for further local studies aimed at improving the plantain production.

Introduction. Nematodes are significant pests of bananas and plantains worldwide. Different levels of susceptibility to these pests have been reported. Studies were carried out to investigate differences in root systems and development of Musa clones with different levels of susceptibility and their possible role in the host-parasite relationship. Materials and methods. Five Musa clones, of which four were susceptible and one resistant to the nematode Radopholus similis, were grown in a plot naturally infested by this nematode. Root samples were collected 6 months after planting and measurements were made on the significance of tissue areas in root cross-sections, and the significance of root mass, root development and nematode populations with depth. Results. No significant difference was observed between cultivars in their general structural organisation or the relative significance of the tissue component of the root cross-section. A significantly lower number of air lacunae was found in the resistant accession in comparison with the susceptible ones. All the accessions except Christine (ABB) were comparable in their root development in the soil profile with more than 70% of the total root mass produced above 40 cm. The greatest nematode population and damage on roots were found at depths between (20 and 40) cm. Conclusions. This is the first report on differences in air spaces between Musa cultivars, and their role in the Musa-nematode relationship needs further investigation.

Introduction. Tephritidae have a major economic importance in the tropical areas. In Benin, we had only very little information available on the mango fruit fly species, except the demonstration of their damage. We therefore carried out the first investigations in Northern Benin during the mango season in 2005. Our objectives were to study fluctuations of tephritid populations in orchards and to assess mango fruit fly infestations and mango losses due to tephritid species. Materials and methods. Experiments were carried out in the Parakou area (Borgou department, Northern Benin). Fruit fly males were captured on mango trees, in two different orchards, with parapheromone traps. To sample and characterize fruit fly species involved in mango infestations, fruits of 17 cultivars were collected in mango orchards from February to June 2005; then, they were brought to the laboratory for emerging species identification. To assess the loss of fruits, sampling of different mango cultivars was achieved in the same orchards. Infested fruits were counted and eliminated; potentially infested fruits were dissected. Results and discussion. Among eight mango fruit fly species found in Benin, four can be considered as species of economic significance: Ceratitis cosyra, C. quinaria, C. silvestrii and Bactrocera invadens. During the dry season, C. cosyra was the most abundant, whereas B. invadens was the most numerous during the rainy season (abiotic factor), in phenological accordance with the ripening of the different mango varieties (biotic factor). From and after mid-May, B. invadens was found more frequently than C. cosyra in the traps and from emergence of infested mangos. Loss averages varied globally from 12% at the beginning of April to 50% in June. Conclusions. Most of the tephritid species found on mangos during our experiments had already been observed previously in other West African countries except B. invadens, an invasive species lately described. Ecological and behavioral studies will be necessary in order to plan and to apply optimal methods for controlling this new pest of major economic importance in West Africa.

Introduction. Rhizobacterial inoculation in low fertilizer-N conditions, viz., 33% fertilizer-N of the total N requirement, could produce similar plant growth to the 100% N-fertilization of banana plantlets grown under hydroponic conditions. Thus, we tested PGPR inoculation in combination with fertilizer-N application to study the role played by strains of rhizobacteria in nutrient accumulation, nitrogen fixation and, consequently, improvement in yield and fruit quality of bananas. Materials and methods. Two PGPR strains were used in the experiments, namely, Sp7 (Azospirillum brasilense) and UPMB10 (Bacillus sphaericus). The design of the experiment was completely randomized with three replications. Eight treatments were applied: control without fertilizer-N application (N0%) and without PGPR; N0% + Sp7; N0% + UPMB10; N33% without PGPR; N33% + Sp7; N33% + UPMB10; N100% without PGPR and N100% + UPMB10. One tissue-cultured banana (cv. ‘Berangan’) plantlet was planted in a plastic pot (4 L) for 45 days and thereafter transferred to a larger polyethylene tank (1000 L) until maturity. A 100-mL broth culture of Sp7 or UPMB10 was added to the respective tanks after the transplanting process and repeat inoculations were performed monthly. The fruits were harvested at the maturity stage after 80–90 days of flowering. After ripening, yield and fruit quality parameters were assessed. Results. Inoculation with 33% fertilizer-N increased the total nutrient accumulation (N, P, K, Ca and Mg). PGPR inoculation along with 33% fertilizer-N significantly increased the bunch yield and fruit physical attributes, namely, finger weight, length and diameter, and [pulp / peel] ratio, besides inducing early flowering by 3 weeks. Conclusion. The results suggested that PGPR strains Sp7 and UPMB10 could be used as bioenhancer and biofertilizer for early, high-yielding and improved banana fruit production in 33% fertilizer-N conditions.

Introduction. Noni (Morinda citrifolia) has a long history related to medical uses in Southeast Asian countries. Today, noni grows in the majority of the southern Pacific areas, in India, the Caribbean, South America and the West Indies. One of the challenges of recent years was to process Morinda citrifolia fruit juice, to make a more modern drug from a traditional product. In order to obtain better understanding of the medicinal characteristics of the noni fruit cultivated in Cambodia, the biochemical and mineral compositions of the raw juice extracted from M. citrifolia fruits were determined. Materials and methods. Whole fresh fruits of M. citrifolia which came to France from Cambodia were preserved at –20 °C during the duration of the experimentation. Commercial Tahitian noni juice was bought pasteurized to be used as a reference. The extraction was carried out on two batches of Cambodian fruits using a hydraulic press. Contents in oil, fatty acids, proteins, amino-acids, sugars and minerals of juices were analyzed. Results. Composition of noni juice of different origin was determined, compared, and discussed in relation to the biochemical and mineral composition of other vegetable oils. Conclusion. The biochemical composition of the noni juice, which showed a high content of antioxidant molecules, is not sufficient to explain the famous medicinal effects of noni juice. Certain molecules, in particular alkaloids, still have to be studied.

Introduction. Pulasan and lychee are from the same family and closely related, therefore the SSR markers are expected to be highly transferable between these two taxa. We investigated the transferability of 12 lychee (Litchi chinensis Sonn.) simple sequence repeat (SSR) loci to pulasan (Nephelium ramboutan-ake L.). Materials and methods. Genomic DNA was extracted from 20 accessions of pulasan for the PCR amplification of the SSR loci using 12 pairs of SSR primers derived from lychee. The PCR products were resolved on denaturing polyacrylamide gels. Results. The percentage of SSR transferability from lychee to pulasan was 58.3% and the percentage of polymorphic SSR markers was 25%. Discussion. The moderate transferability and low polymorphism rates suggest the possibility of interruptions within the repeat motif and mutations in the flanking sequences of SSR repeat motifs. Our results did not reveal a high rate of transferability between lychee and pulasan. However, this study showed that the SSR markers developed in lychee are a good source of molecular markers for pulasan.

Introduction. In Southern Cameroon, bananas and plantains (Musa) play an important role in the population’s diet. There are many food uses of these crops relative to the eating habits of consumers. Our study was carried out in order to list the varieties of bananas and plantains mostly used by housewives and restaurant dealers and to describe the various culinary preparations used for their transformation. Methods. The processing and culinary methods of bananas and plantains, including the estimation as well as the measurement of the quantities of ingredients used, and the traditional utilisations of these foodstuffs, were investigated in two Cameroonian towns (Bafoussam and Yaoundé). Results. Some culinary preparations using different varieties are common in Southern Cameroon such as roasted or fried plantain, plantain chips, boiled plantain or banana and pounded plantain. They are eaten with various sauces, vegetables and other food complements. Other preparations found in these regions include stuffed plantain or banana, plantain or banana porridges and traditional recipes called kondre and malaxé. Preparation of chips, fried and roasted plantain are mainly carried out by women and young boys on the streets in an effort to diversify sources of income. These various transformation and uses of bananas and plantains contribute to the reduction of post–harvest losses as well as the valorisation of these perishable food stuffs. Conclusion. The evaluation of their nutrient composition (macro- and micronutrients) as well as the effects of culinary preparations and the bio-availability of those nutrients are being conducted at the CARBAP Post–Harvest Technology Laboratory in order to appreciate their contribution in the fight against malnutrition in some regions of Cameroon.

Introduction. The determination of an adequate container volume that combines rational use of substrate with maximization of vegetative growth is very important to optimize citrus nursery tree production. This experiment aims to evaluate the influence of container volumes on vegetative growth of citrus nursery trees. Materials and Methods. Pera sweet orange nursery trees [Citrus sinensis (L.) Osbeck] budded on Rangpur lime (Citrus limonia Osbeck) were produced in six container volumes [(3.0, 3.8, 4.5, 4.6, 5.0 and 5.8) L], with the respective container dimensions of [(20 × 32, 20 × 35, 22 × 32, 22.5 × 35, 25 × 32 and 25 × 35) cm]. Another 5.0-L container studied had the dimensions of 20 cm x 40 cm. Commercial substrate was composed of Pinus bark and a controlled-release fertilizer was used. Parameter evaluation started after moving the rootstocks from seedling trays, 3.5 months after sowing, to plastic containers and continued until nursery trees reached one year old. The studied parameters were shoot height, diameter and leaf area of rootstocks and nursery trees, bud take percentage and scion and root dry matter of nursery trees. Results and discussion. The development of Rangpur lime plants was not affected by any treatment until budding. The largest container volumes induced faster and more vigorous vegetative development of Pera sweet orange nursery trees budded on Rangpur lime. A 5.0-L container volume could be indicated as a technical and economical option for the production of containerized citrus nursery trees.

Introduction. Chlorophyll fluorescence (chl-fluorescence) has been used in postharvest studies as a non-destructive technique for evaluating fruit ripening. Since there are no available studies using chl-fluorescence in guava fruit, the aim of this work was to verify the relations between chl-fluorescence parameters and fruit quality attributes, such as skin color and fruit firmness, and to measure the chl-fluorescence during ripening of guava fruit. Materials and methods. Firstly, maximal (Fm), minimal (Fo), variable (Fv), and variable to maximal [Fv/Fm] fluorescence yields, skin color (Hº) and fruit firmness were evaluated in guava fruit harvested at three ripeness stages: dark-green (I), light-green (II) and yellowish-green (III). Secondly, changes in the above chl-fluorescence parameters and Hº were measured during 7 days of ripening. Relations between the evaluated parameters were also studied. Results and discussion. The three ripeness stages were well segregated using the Hº, Fm and fruit firmness parameters. Fo was insensible to early changes in fruit ripening, maintaining relatively stable values until fruit firmness of 20 N. When considering changes in chl-fluorescence and Hº during ripening, there were no significant differences between guava fruit harvested at stages II or III. The [Fv/Fm] value decline was only evident on the fifth day of ripening, whereas Fv, Fm and Hº began to decrease on the first day. Regardless of [Fv/Fm], the relations between chl-fluorescence parameters and Hº tended to increase from ripeness stages I to III, with Fm having the highest correlation with Hº. The results show that chl-fluorescence can be used to evaluate the ripening and senescence of guava fruit, with Fm being a good ripening indicator.

Introduction. The citrus industry is one of the main activities of Brazilian agriculture. Several pests and diseases have threatened citrus culture in recent years. Genetic mapping is one of the most efficient strategies for conducting advanced genetic studies by facilitating plant selection guided by markers. The objective of this study was to construct an integrated genetic map between Citrus sinensis (L.) Osbeck cv. ‘Pêra’ and C. reticulata Blanco cv. ‘Cravo’ using two different types of segregation of markers. Materials and methods. The linkage analyses were conducted with segregation data obtained from 256 RAPD markers in a population of 94 hybrids. Analyses were performed through the software JoinMap, LOD ≥ 6.0, θ ≤ 0.25, and the Kosambi function. Results and discussion. The linked map between the two cultivars had 217 markers defined by 15 linkage groups, covering 527 cM. This map had five linkage groups with common markers of ‘Pêra’ and ‘Cravo’. The inclusion of new markers would increase the number of linkage groups with markers from both parents, thus making their number equal to the haploid chromosome number. The alterations in the order and in the distances among the markers, due to the presence or absence of bridging markers in the linkage map, are discussed.

Introduction. La banane et le plantain occupent une place importante dans l’économie du Cameroun. Ces fruits sont consommés sous diverses formes et ils entrent dans l’alimentation de base des populations. L’utilisation des champignons mycorhiziens à arbuscules peut favoriser une bonne croissance des bananiers. Une étude a été conduite en pots sous ombrière au Cameroun avec des vitroplants de bananier plantain (cv. Bâtard) pour évaluer leur réaction à la mycorhization sur cinq sols de fertilité différente. Matériel et méthodes. Les vitroplants de bananier plantain ont été inoculés pendant la première phase de sevrage avec une souche locale de champignons mycorhiziens à arbuscules du genre Glomus sp. Un mois après inoculation, les plants ont été transférés sur cinq types de sols différents. Les paramètres de croissance (circonférence, hauteur du pseudo-tronc, nombre de feuilles et surface foliaire de la dernière feuille émise, ainsi que poids frais et sec de la plante) et de mycorhization (fréquence et intensité) ont été observés huit et douze semaines après inoculation. Résultats et discussion. Les observations réalisées ont montré que les plants inoculés ont eu une croissance significativement plus élevée que les plants non inoculés et cela quel que soit le type de sol. Le poids frais et le taux de matière sèche ont présenté également des valeurs plus élevées sur les plants inoculés. Le taux de colonisation racinaire par le champignon a été meilleur sur les sols pauvres. Conclusion. La mycorhization des bananiers plantains a eu un effet bénéfique non négligeable sur certains sols riches, mais cet effet a été plus important encore sur les sols pauvres. La mycorhization pourrait donc permettre d’améliorer la croissance et la production des bananiers plantains sur des sols à faible fertilité ; ces résultats obtenus en conditions contrôlées devront être confirmés par des essais en grandeur réelle.

Introduction. The chataigne or breadnut, Artocarpus camansi Blanco, has high nutritive value but it is an under-utilised food source. Yield losses due to tree height and limited information on productivity are constraints to commercial production. Our study was undertaken to determine fruit yield and seed yield, the relationship between fruit size and seed yield, and the response of yield to pruning. Materials and methods. Fruit and seed yield data were collected from 1996 to 2002 from three seedling trees established at the University of the West Indies in Trinidad and Tobago in 1993. The trees were pruned in December 1998. Results. The highest fruit mass per tree (139.7 kg), fruit number per tree (126) and seed mass per tree (59 kg) were obtained in 5-year-old trees. Fruit and seed yields were significantly (P < 0.001) lower in the years after pruning. Fruit mass per tree was positively correlated with fruit number (r = 0.99). Seed mass per fruit was positively correlated with seed number per fruit (r = 0.87) and both variables had strong, positive correlations with mean fruit mass (r = 0.83 and r = 0.77, respectively) and fruit volume (r = 0.63 and r = 0.67, respectively). Discussion and conclusions. Chataigne fruit and seed yield potential is greater than originally estimated. Both are strongly related and selection for high seed number per fruit with more effective pollination, disease control and proper tree height management may further increase productivity. In the field, estimated fruit volume is the most practical indicator of seed yield.

Introduction. Root restriction occurs when seedlings are grown in increasingly small containers and it reduces plant growth in different ways. Therefore, the objectives of our study were to investigate the effects of varying container sizes and irrigation frequency on growth parameters of ‘Rough lemon’ (C. limon) plants Maseno, Kenya. Materials and methods. The treatments tested the effect of three container volumes (1.7 L, 2.7 L and 4.5 L) and three irrigation frequencies [every day (W1), every two days (W2) and every 3 days (W3)]. The design of the experiment was completely randomized with three replications. Growth parameters studied were plant height, canopy height, shoot and root weight, number of leaves and shoot to root ratio. Results and discussion. Increasing container volumes generally increased the height of plants, height of canopy, weight of whole plants and weight of roots, but it did not affect number of leaves, stem diameter or shoot to root ratio. Irrigation frequency increased number of leaves, height of plants, height of canopy, stem diameter and weight of shoots and roots, but this factor had no effect on weight of whole plants. These findings are explained by reduced root restriction in the largest container volumes. Conclusion. Increasing container volumes from 1.7 L to 4.5 L and irrigation frequency from every 3 days to every day increases plant growth as expressed in the various plant growth parameters.