Ideas 1. General combining ability (GCA) effects were superior over specific combining ability (SCA) effects indicating that additive genes largely controlled grain yield and other traits among the newly developed extra-early quality protein maize inbred lines under low nitrogen, Striga-infested and high nitrogen conditions. 2. Maternal genetic effects influenced plant height under Striga-infested condition which suggested that inbred lines that exhibited significant and positive GCA-female effects for plant height should not be used as female parents to avoid production of tall hybrids that are liable to lodging. 3. Genetic distances were significantly associated with grain yield under low nitrogen, Strigainfested and high nitrogen conditions which implied that inbred lines that had high pairwise genetic distances should be considered for hybrid production to maximize heterosis. This article is protected by copyright. All rights reserved. 2 4. TZEEQI 358 displayed significant and desirable GCA effects for grain yield and other important traits across low nitrogen, Striga-infested and high nitrogen conditions and could be a useful source of valuable alleles for population improvements. 5. TZEEIORQ 58 x TZEEQI 397 exhibited high grain yield and stability across the low nitrogen, Striga-infested and high nitrogen environments and could potentially address the food and nutritional insecurities prevailing in sub-Saharan Africa.

Tailored interventions in the tomato sector require current information on production and marketing systems along with the constraints faced by the stakeholders. We conducted this study to understand the current production practices, stakeholders’ varietal preferences, tomato market trends, and challenges along the crop’s value chains. A multistage sampling method coupled with a random walk was used to identify survey locations and identify 180 respondents across seven regions in Ghana. The study showed that tomato was predominantly produced by male (81%) and literate farmers (84%). Tomato farmers were smallholder farmers generally cultivating less than five acres. Tomato was mainly cultivated under rainfed conditions. Farmers used both bought seeds and their own saved seeds for production. Farmers in Bono, Greater Accra, and the Upper East region largely cultivated improved tomato varieties, while farmers in the Bono East region cultivated local varieties. Across the regions, being a male and having access to irrigation facilities increased the probability of using improved varieties by 19% and 51%, respectively. The most important farmer and market preference criteria included high yield, medium to large fruit size and rounded fruit shape, red color, time to maturity and disease resistance. The major production challenges of tomato production included diseases, pests, and poor access to water for irrigation. The average yield of tomato varied from 6902.26 kg/ha in the Bono Region to 16,213.98 kg/ha in Bono East. Tomato was exclusively produced for fresh market. The major marketing challenges were low producer prices, low demand for produce, and competition from other farmers. This study provides key information to improve tomato value chains and guide the introduction or breeding of improved tomato varieties.

Information on the genetic diversity, population structure, and trait associations of germplasm resources is crucial for predicting hybrid performance. The objective of this study was to dissect the genetic diversity and population structure of extra-early yellow and orange quality protein maize (QPM) inbred lines and identify secondary traits for indirect selection for enhanced grain yield under low-soil nitrogen (LN). One hundred and ten inbred lines were assessed under LN (30 kg ha -1) and assayed for tryptophan content. The lines were genotyped using 2500 single nucleotide polymorphism (SNP) markers. Majority (85.4%) of the inbred lines exhibited wide pairwise genetic distances between 0.4801 and 0.600. Genetic distances were wider between yellow and orange endosperm lines and predicted high heterosis in crosses between parents of different endosperm colors. The unweighted pair group method with arithmetic mean (UPGMA) and the admixture model-based population structure method both grouped the lines into five clusters. The clustering was based on endosperm color, pedigree, and selection history but not on LN tolerance or tryptophan content. Genotype by trait biplot analysis revealed association of grain yield with plant height and ear height. TZEEQI 394 and TZEEIORQ 73A had high expressivity for these traits. Indirect selection for high grain yield among the inbred lines could be achieved using plant and ear heights as selection criteria. The wide genetic variability observed in this study suggested that the inbred lines could be important sources of beneficial alleles for LN breeding programs in SSA.