NDVI and grain fill duration are important to be considered in breeding for terminal heat stress tolerance in wheat

Abstract

Terminal heat stress is a major constraint for taking a profitable crop of wheat by small and marginal farmers in the Indo‐Gangetic Plains of south Asia. Hence, breeders remain in constant search for heat‐tolerant genotypes. This study was done with the purpose to find out high‐yielding wheat genotypes that perform stably under terminal heat stress as well as to conclude an easy phenotyping trait for this objective. A cross (HUW 234 × HUW 468) was made using two popular cultivars of the eastern Gangetic Plains of India. HUW 234 carries terminal heat tolerance whereas, HUW 468 is high yielding but suffers from terminal heat stress when planted late. So obtained 167 recombinant inbred lines (RILs) were exposed to both timely sown (TS) and late sown (LS) conditions at three locations for two consecutive years 2016–17 and 2017–18 at Varanasi (Uttar Pradesh), Jabalpur (Madhya Pradesh) and Pusa, Samastipur (Bihar). Combined ANOVA revealed that normalized difference vegetation index (NDVI) at anthesis stage (NDVI_AH) and grain filling duration (GFD) was significant for genotype (G), environment (E) and genotype × environment interaction (GEI). Likewise, differences were significant for grain yield (GY) and 1000‐grain weight (TGW). AMMI analysis revealed similar results. However, NDVI_AH showed low variation under heat stressed late sown conditions. Furthermore, the which‐won‐where model and mean versus stability identified the best performing, above‐average yielding and stable lines across the environments. Correlation among measured traits revealed that NDVI_AH had a significant association with GY in most of the environments. Several lines that performed superior to better parent for GY also showed higher values for NDVI_AH and GFD. The study demonstrates that NDVI_AH and GFD appear to be important traits to be considered while breeding for terminal heat stress tolerance in wheat.

RETRACTED: Assessing Heat Stress Tolerance and Physiological Adaptations in Wheat Varieties: A Comprehensive Study on Phenotypic Parameters and Physiological Responses

“…This suggested that the heat stress had no impact on the overall greenness of the wheat cultivar. Kumar et al, 2023 reported that the NDVI value at the anthesis stage and grain lling stage was crucial for understanding the heat stress tolerance capacity of wheat. NDVI value was not statistically signi cant among the two treatments which implies that the variety of wheat is somewhat resistant to heat stress.…”

Table_7.xlsx

“…The possible use of SEMs to understand physiological causes of genotype by environment or management interaction was explored by Vargas et al (2007), who concluded that the approach can facilitate the understanding of the effects of environmental covariates on yield performances or can be used to generate hypotheses (Valente et al, 2013). Under heat stress, SEM confirmed the role of HDD_A and HDD_GF in controlling NDVI (as NDVI and IT_NDVI), hence plant growth and biomass development, which in turn plays a key pivotal role in influencing of PH, KNS, TKW and finally GY, as recently pointed out by Kumar et al (2023).…”