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Amaranth (Amaranthus sp.) is an important leafy vegetable in Africa where most farmers grow unimproved landraces. Information about amaranth genetic diversity and its adaptation to different environments will help breeders develop improved commercial varieties that meet market requirements. The objectives of this study were to investigate the performances of amaranth entries for vegetable yield across locations and seasons, assess the relative contributions of genetic vs. environmental sources of variation to yield, and cluster locations into mega-environments (MEs) to suggest future test sites. Twenty-six diverse entries were evaluated for vegetable yields in replicated trials at five locations in wet-cool and hot-dry seasons in Tanzania. Season explained the highest proportion (52.1%) of the total sum of squares followed by entries (24.9%) and locations (23.0%). Mean yield across the hot-dry season trials (27.7 t·ha−1) was 47.3% greater than the mean yield across wet-cool season trials (18.8 t·ha−1). Differences among entries in vegetable yield were higher in the hot-dry season than in the wet-cool season, indicating that gain from selection is likely to be greater in the hot-dry season. Most entries performed well in either wet-cool or hot-dry season but a few entries were adapted to both seasons. Two MEs were identified, one characterized by lower altitudes, higher temperatures, and less fertile soils, and a second ME associated with higher altitudes, lower temperatures, and more fertile soils. Each ME may serve as an initial selection site for their respective target environment. Targeting a specific season may give a better chance of finding high-yielding varieties.

Amaranth is one of the most commonly produced and consumed indigenous vegetables on the African continent. In Tanzania amaranth constitutes about 5.3% of total vegetable hectarage planted annually. Most cultivated varieties of amaranth are landraces with relatively poor leaf and grain yield. This study was conducted to identify genotypes with potential for dual purpose (leaf and grain) use for promotion or further cultivar development. An experiment was carried out in two seasons at AVRDC -The World Vegetable Center in Arusha, Tanzania from Feb to May and June to Sep 2012. Fourteen genotypes were used in a randomized complete block design. Results indicated that leaf yield differed significantly among the genotypes in both trial 1 (p ≤ 0.01) and 2 (p ≤ 0.05). The highest leaf yields were obtained in genotypes RVI00117 (32.8 t/ha) and RVI00002 (14 t/ha) in trial 1 and 2, respectively. The lowest leaf yields were obtained from genotypes RVI00121 and RV00090 (4 and 6.3 t/ha) in trials 1 and 2, respectively. There were significant differences (p ≤ 0.001) among genotypes for grain yield obtained after leaf harvesting. Genotype RVI00022 had the highest seed yield (1971.3 kg/ha) over the two seasons. Where leaf was not harvested, genotype RVI00121 had the highest seed yield (2920 kg/ha) over the two seasons. From this study, we recommend genotypes RVI00121 and RVI00001 for grain production. For dual purpose use, we recommend RVI00007 during warm and wet conditions and RVI00022 during cool and dry condition.

No abstract

Amaranths (Amaranthus sp.) are a popular leafy vegetable grown and consumed by resource-poor people in many African countries. Greater awareness of the importance of nutritious foods has increased demand by African consumers for amaranth. Presently, most African farmers grow low-yielding local varieties of variable seed quality. High-yielding amaranth varieties that are adapted to the major agro-ecologies of eastern and southern Africa possess key traits needed by male and female farmers and meet diverse market preferences are required. The objective of this study was to identify amaranth lines adapted to major amaranth production environments in Kenya and Tanzania using a gender-disaggregated farmers participatory approach to explore possible gender differences in trait and variety preferences. Twenty amaranth entries were evaluated for vegetable yield, agronomic traits, and organoleptic taste tests in replicated, farmer-participatory variety selection trials at one location in Kenya and at four locations in Tanzania. Differences among entries (G), locations (E), and G × E interaction were significant or highly significant for marketable vegetable yield. Location followed by entry was the most important factor that explained differences in yield. G and G × E interaction biplot analysis classified the five locations into two different mega-environments, mainly based on altitude, temperatures, and soil characteristics. Marketable vegetable yield was positively correlated with leaf length, plant height, and the selection scores of female and male farmers at almost all locations. Selection scores of female and male farmers were positively correlated, indicating that male and female farmers shared similar amaranth variety preferences. Farmers identified and ranked important traits that can be used by breeders to design amaranth product profiles and develop amaranth breeding objectives. Lines combining high yield with high farmer and consumer preference scores have been retained for distinctiveness, uniformity, and stability tests for possible release as commercial varieties.