RESUMO
This work aimed at evaluating and comparing agronomic characteristics of 15 quinoa (Chenopodium quinoa Willd) genotypes cultivated in two altitudes and sowing densities. The experiment initiated by individual plant selection in Brasília, DF, followed by progeny evaluation in Colombia, at 1,100 m and 1,850 m altitude and population densities of 30 and 12 plants m-1, with row spacing of 0,50 m. Eleven progenies and four commercial cultivars were tested. The progenies were obtained by selecting individuals in BRS Syetetuba based on plant height, grain and dry matter yield, harvest index and 1,000 grain weight. The genotypes with the highest grain yield were BRQ 8 (2,283 kg ha-1), Aurora (2,121 kg ha-1) and BRQ 4 (2,043 kg ha-1). In general, the genotypes had early plant cycle, from emergence to physiological maturity of 100-110 days at high plant density for the two altitudes. It is concluded that exploring variability in progenies originated from natural crosses is effective in the adaptation of quinoa to tropical environments. Moreover, genotypes tested in the Cerrado (Brazilian Savannah) maintain the same response relation when evaluated in Colombia. (AU)
Este trabalho teve por objetivo avaliar e comparar características agronômicas e biométricas de 15 genótipos de quinoa (Chenopodium quinoa Willd), cultivados em duas altitudes e densidades de semeadura. O experimento iniciou por seleção individual em Brasília, DF, seguido por avaliação agronômica em duas altitudes (1,100 m e 1,850 m), e duas densidades de semeadura (30 plantas m-1 e 12 plantas m-1) na Colômbia. O experimento foi constituído por 11 progênies e quatro cultivares comerciais em uso na Colômbia. Na seleção, consideraram-se altura de plantas, produção de grãos e massa seca, índice de colheita e peso de 1000 grãos. Os genótipos que se destacaram para rendimento foram BRQ 8 (2,283 kg ha-1), Aurora (2,121 kg ha-1) e BRQ 4 (2,043 kg ha-1). Em geral, os genótipos apresentaram precocidade, com ciclo (emergência-maturação) entre 100 e 110 dias, com densidade ótima de 30 plantas m-1 nas duas altitudes. Conclui-se que a exploração de variabilidade em progênies oriundas de cruzamentos naturais, mostra-se efetiva na adaptação de quinoa a ambientes tropicais. Ademais, genótipos selecionados no Cerrado mantêm as mesmas relações de resposta quando avaliados na Colômbia. (AU)
Assuntos
Produção Agrícola , Chenopodium quinoa , Agricultura SustentávelRESUMO
Maintaining wheat productivity under the increasing temperatures in South Asia is a challenge. We focused on developing early maturing wheat lines as an adaptive mechanism in regions suffering from terminal heat stress and those areas that require wheat adapted to shorter cycles under continual high temperature stress. We evaluated the grain yield performance of early-maturing heat-tolerant germplasm developed by CIMMYT, Mexico at diverse locations in South Asia from 2009 to 2014 and estimated the breeding progress for high-yielding and early-maturing heat-tolerant germplasm in South Asia. Each year the trial comprised of 28 new entries, one CIMMYT check (Baj) and a local check variety. Locations were classified by mega environment (ME); ME1 being the temperate irrigated locations with terminal high temperature stress, and ME5 as hot, sub-tropical, irrigated locations. Grain yield (GY), days to heading (DTH) and plant height (PH) were recorded at each location. Effect of temperature on GY was observed in both ME1 and ME5. Across years, mean minimum temperatures in ME1 and mean maximum temperatures in ME5 during grain filling had significant negative association with GY. The ME1 locations were cooler that those in ME5 in the 5 years of evaluations and had a 1-2 t/ha higher GY. A mean reduction of 20 days for DTH and 20 cm in PH was observed in ME5. Negative genetic correlations of -0.43 to -0.79 were observed between GY and DTH in South Asia during 2009-2014. Each year, we identified early-maturing germplasm with higher grain yield than the local checks. A positive trend was observed while estimating the breeding progress across five years for high-yielding early-maturing heat tolerant wheat compared to the local checks in South Asia. The results suggests the potential of the high-yielding early-maturing wheat lines developed at CIMMYT in improving wheat production and maintaining genetic gains in South Asia.