Attempts to develop high yielding varieties in Ghana have mostly relied on the introduction of new clones to broaden the range of planting materials for yield improvement. The objective of this study was to estimate the genetic variation and heritability for bean yield of six recommended cocoa clones using these as males in crosses with five seed garden parents. Twenty-four families obtained from a 5 × 6 North Carolina II (NC II) incomplete factorial mating design together with 19 high yielding single crosses, of which four were standard mixed hybrids, were planted in a randomized complete block design with four replications and evaluated for bean yield over 6 years. To account for the serial correlation among yield data collected from the same plants over years, six models with different covariance structures were tested. The general covariance model emerged appropriate based on Akaike information criterion values with significant (P < 0.01) family × year interaction. Average bean yield was highest in the NC II families followed by the specific crosses then the standard mixed hybrids. Combining ability analysis among the NC II was significant for female, male and female × male interaction along with a narrow-sense heritability of 0.26. Clone CRG 6035 among the males which had good general combining ability could be added to the seed garden parents, while the promising hybrids (NA 33 × SCA 9, SCA 6 × Pound 10, T60/887 × PA 121 and T79/501 × CRG 6035/103) undergo stability tests before release.

In drought-affected maize production zones with short growing periods, the development and use of early maturing drought-tolerant cultivars can stabilize maize production. We evaluated 10 improved and 25 farmers' early maturing maize varieties under moisture deficit and well-watered conditions for 2 years to identify suitable genetic materials for breeding drought-tolerant cultivars. The varieties exhibited significant differences in grain yield and other traits under both moisture deficit and well-watered conditions. Changes in the rank order of the varieties for grain yield was not significant across the different levels of moisture supply in this study. Grain yield was significantly correlated with days to anthesis, days to silking, plant height, ear height, ear number and anthesis–silking interval (ASI) under the two irrigation treatments and with leaf death scores under moisture deficit, suggesting that the common traits were beneficial in maximizing grain yield under both sufficient water supply and moisture deficit. Grain yield and the traits significantly correlated with it differentiated the early maturing maize varieties into two distinct groups under well-watered condition and moisture deficit. The improved varieties were superior to the farmers' varieties in grain yield and other traits under moisture deficit, possibly due to selection of their progenitors for improved performance in multiple locations. We found some farmers' and improved varieties with similar yield potential and flowering time under well-watered conditions but with marked differences in grain yield and other traits under moisture deficit. Use of such promising landraces that would also be invaluable sources of desirable farmers-preferred end-use quality traits in combination with promising improved varieties as breeding materials could enhance the genetic grain from selection for drought tolerance in early maize.