Authors:S. Sareen, R. Munjal, N. Singh, B. Singh, R. Verma, B. Meena, J. Shoran, A. Sarial, and S. Singh
Terminal heat, which is referred as increase in temperature during grain filling, is one of the important stress factors for wheat production. Current estimates indicate that wheat crop grown on around 13.5mha in India is affected by heat stress. In order to meet the challenges of high temperature ahead of global warming, concerted efforts are needed to evaluate germplasm for heat tolerance and identify and develop genotypes suitable for such stressed environments. The advanced wheat genotypes developed for stress and normal environments by different research centers were evaluated across 7 locations representing varied agroclimatic zones during 2007–08 and 2008–09 to study their adaptability for heat stress and non-stress environments. The additive main effects and multiplicative interaction analysis for G × E interactions revealed differences amongst locations to phenology and grain yield. Genotype RAJ 4083 developed for cultivation under late sown conditions in peninsular zone was also found adaptable to timely sown conditions. Similarly, HD 2733 a cultivar of NEPZ timely sown conditions and PBW 574 an advanced breeding line of NWPZ late sown conditions was found adapted to Peninsular zone. The cultivar RAJ 3765 showed specific adaptability to Pantnagar in NWPZ. Genotype NW 3069 developed for NEPZ timely sown conditions have shown adaptability to number of locations; timely sown conditions at Karnal and Hisar in NWPZ and Niphad in PZ. Likewise, WH 1022 developed for NEPZ late sown conditions exhibited specific adaptability to all timely sown locations in NWPZ.
The genotype by
environment (GE) interaction is a major problem in the study of quantitative
traits because it complicates the interpretation of genetic experiments and
makes predictions difficult. In order to quantify GE interaction effects on the
grain yield of durum wheat and to determine stable genotypes, field experiments
were conducted with ten genotypes for four consecutive years in two different
conditions (irrigated and rainfed) in a completely randomized block design with
three replications in each environment. Combined analysis of variance exhibited
significant differences for the GE interaction, indicating the possibility of
stable entries. The results of additive main effect and multiplicative
interaction (AMMI) analysis revealed that 12% of total variability was
justified by the GE interaction, which was six times more than that of
genotype. Ordination techniques displayed high differences for the interaction
principal components (IPC1, IPC2 and IPC3), indicating that 92.5% of the GE sum
of squares was justified by AMMI1, AMMI2 and AMMI3, i.e. 4.5 times more than
that explained by the linear regression model. The results of the AMMI model
and biplot analysis showed two stable genotypes with high grain yield, due to
general adaptability to both rainfed and irrigated conditions, and one with
Nine bitter vetch selection lines were evaluated in three successive years to determine their yield and seed index (100-seed weight) stabilities, based on three parameters: phenotypic index (P), regression coefficient (bi), and least deviation from regression (S2 di). The line Sel. 2517 (L7) was identified as the most stable one for the growing seasons, while Sel. 2509 (L2) and Sel. 2511 (L4) were found to be stable for seed yield under favourable climatic conditions. For seed index Sel. 2515 (L6) was identified as the most stable line. Selection line 2513 (L5), which originated from Cyprus, had the highest degree of responsiveness to changing environments.
Authors:M. Studnicki, M. Wijata, G. Sobczyński, S. Samborski, and J. Rozbicki
Eleven spring wheat cultivars were compared in terms of the stability of their grain yield and grain quality. The cultivars’ stability was evaluated separately at two different crop management levels – moderate-input management and high-input management. Three stability models were used for the two crop management levels based on a linear mixed model framework with restricted maximum likelihood. The Shukla model was the most appropriate for the evaluation of stability of tested spring wheat cultivars. The thousand-grain weight, starch content, Zeleny sedimentation value and test weight were characterized, and the stability ranking cultivars at moderate-input management level was mostly consistent with the rank of cultivars 24 for high-input management level. For grain yield, grain protein content and wet gluten content, the stability rankings were not consistent. Cultivars ‘Monsun’ and ‘Parabola’ are the most stable cultivars for grain yield in moderate-input management and high-input management, respectively. Cultivar ‘Hewilla’ was the stable cultivar for all quality traits at moderate-input management. Cultivar ‘Arabella’ was the most stable cultivar at high-input management level.