RESPONSE OF SOME BREAD WHEAT GENOTYPES TO HEAT STRESS | ||||
| Egyptian Journal of Plant Breeding | ||||
| Article 9, Volume 24, Issue 1, March 2020, Page 137-158 PDF (893.18 K) | ||||
| Document Type: Original research | ||||
| DOI: 10.12816/ejpb.2020.199311 | ||||
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| Abstract | ||||
| The present investigation was undertaken to understand the impact of higher temperature on yield attributing traits and to select higher heat stress tolerant genotypes for future breeding program. To fulfill the requirement of this objective, the experiment was conducted in three successive seasons 2015/2016, 2016/2017 and 2017/2018. At each season three sowing dates were used i.e. normal (20th Nov.), 10th Dec. and late sown (30th Dec.) as heat stress conditions with 12 diverse genotypes. The analysis of variance combined across the three successive seasons of strip plot design for studied traits revealed that the seasons (S), dates (D), genotypes (G), SD, SG, DG, SDG had highly significant variation (p < /em>≤ 0.01) for all studied traits, except SD and SDG were insignificant for grain yield. In the present study, genotypes were classified arbitrarily into four different categories according to heat susceptible index (HSI) i.e. highly heat tolerant (HSI < 0.50), heat tolerant (HSI: 0.51-0.75), moderately heat tolerant (HSI: 0.76 – 1.00) and heat susceptible (HSI > 1.00).Results revealed that on the basis of HSI, the local cultivar Misr 2 was the most desirable under heat stress as it attained high to moderate HSI values for yield and its attributing traits. Similarly, Sids 4 was found desirable as it attained moderate HSI values for four traits (plant height, days to maturity, No. of kernels spike-1 and 1000-kernel weight). However, Sids 1, Shandaweel 1, Sids 12 and Line#3 were desirable as they attained moderate HSI values for three traits. Meanwhile, Misr 1 Sakha 95, line#1 and line#2 exhibited only two traits moderate to HIS values. The last place for genotypes was shown by Giza 168 and Gemmiza 1, which exhibited only one trait moderate to HSI values. Therefore, Misr 2, Sids 4, Sids 1, Shandaweel 1, Sids 12 and Line#3 may perform as potential donor for heat tolerance. Relative heat tolerance (RHT) for the studied traits of the genotypes in the late sowing date (heat stress) with respect to their corresponding normal sowing date, showed that Misr 2 was the lowest RHT in No. of kernels spike-1 and grain yield (-11.18% and -26.27%, respectively). The correlation between No. of kernels spike-1 and grain yield showed significantly positive association (r = 0.225*). The coefficient of determination (R2) revealed that 5.1% of total variability in grain yield was due to its association with No. of kernels spike. The correlation between 1000-kernel weight and grain yield showed significantly positive association (r=0.441**). The coefficient of determination (R2) revealed that 19.4% of total variability in grain yield was due to its association with 1000-kernel weight. Based on simple regression analysis, unit increase of No. of kernels spike-1 and 1000-kernel weight it leads to increase the grain yield plant-1 by 1.99 and 1.901 units, respectively. | ||||
| Keywords | ||||
| Bread wheat; Triticum aestivum L; Heat stress; Heat Susceptibility Index; Simple correlation | ||||
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