Adaptation of soybean (Glycine max (L.) Merrill) to the dry season of the tropics. I. Genotypic and environmental effects on phenology

Abstract

Eight soybean genotpes were sown at weekly intervals in three tropical dry season enviroments to examine genotypic and environmental effects on phenology. A series of simple linear models was used to test the relationships, for individual genotypes, between rate of development for the vegetative (Rf) and reproductive (R,) phases and photoperiod and temperature. For each genotype, most (> 85%) of the variation across sites, years and sowing dates in Rf and more than half the variation in R, could be accounted for by variation in photoperiod and/or temperature. Rf was generally negatively associted with mean maximum temperature and mean photoperiod, and positively with mean minimum temperature. R, was generally positively associated with either mean, or mean maximum, temperature and negatively with mean photoperiod. It was concluded that variations in photothermal regime across sites, years and sowing dates within the tropical dry season are sufficiently large to induce instability in time to flowering of most present soybean cultivars. Most genotypes are also poorly adapted to the relatively long day-warm temperature conditions experienced by dry season crops during podfilling, presumably because they have been developed as summer crops. Breeding soybeans for the dry season will therefore need to place strong emphasis on photothermal effects during post-flowering as well as pre-flowering development.

Genotype × Environment Interactions and Yield Stability of Food-Grade Soybean Genotypes

“…Seed yield and biomass were significantly correlated at the three locations (Table 3) A linear relationship between biomass and seed yield was reported for soybean in Puerto Rico (Ramirez‐Oliveras et al, 1997) and Australia (Mayers et al, 1991). Board et al (1996) reported strong positive correlations between yield and top dry matter at the R5 stage for late planted soybean.…”

A comparison of six vetches (Vicia spp.) for developmental rate, herbage yield and seed yield in semi‐arid central Turkey

“…Moreover, Saxena () suggested that grain legumes with longer crop growth duration have lower harvest index, chiefly because of the prolonged period of vegetative growth. Harvest index was negatively correlated with the length of growth season as biomass accumulation was progressively increased with longer crop duration (Lawn and Byth ; Mayers et al ., ).…”

“…The different sowing dates in spring provided an additional diversity for the adaptation of Sat. In soybean, biomass production is mostly a function of crop growth longevity, which is mainly related to genotypic maturity and sowing date (Lawn and Byth, ; Mayers et al ., ; Lawn and James, ). As a summer crop, Sat is already phenologically adapted to the short growing season in central Turkey.…”

Ocorrência E Intensidade De Doenças Foliares E Ciclo De Cultivo Em Seis Cultivares De Soja Durante Duas Épocas De Semeadura

“…Diferenças entre as épocas de semeadura, possivelmente foram devidas à temperatura, a mesma que variou entre uma época e outra (Hadley et al, 1984;Mayers et al, 1991;Garcés-Fiallos et al, 2014). Essas diferenças também podem existir quando é comparada a duração do ciclo de cultivo em outras latitudes.…”