VARIATIONS AMONG MAIZE (Zea Mays L.) HYBRIDS IN RESPONSE TO HEAT STRESS: HYBRIDS SELECTION CRITERIA

Abstract

High ambient temperature is one of the most alarming climatic factors in challenging the productivity and sustainability of crops worldwide. An effective way to cope this problem is the development of climate smart, heat resilient maize hybrids through evaluating the cultivated germplasm. The main objective of current study was to evaluate local and multinational maize hybrids for their performance under optimal and heat stress conditions and to devise a selection criterion for the identification of heat tolerant maize hybrids. Nine maize hybrids, including local and multinational, were evaluated under optimal and heat stress conditions across three consecutive spring seasons (2017-18, 2018-19 and 2019-20) at Maize and Millets Research Institute, Yusafwala, Sahiwal. Results revealed the presence of highly significant differences among maize hybrids under both conditions and for all three seasons. Kernel yield was found to be highly correlated with net photosynthetic rate (0.735 ** ), shelling percentage (0.910 ** ) and relative cell injury percentage (-0.775 ** ) under stress conditions. Cluster and biplot analysis unveiled that two local maize hybrids YH-5507 and YH-5427 were highly heat tolerant while multinational hybrids i.e. NK-8711, P-1543 and DK-6724 were highly productive under control/optimal conditions only. These hybrids can be invaluable sources of genes/alleles for the development of climate smart maize genotypes.

Determining the Grain Yield and Nutritional Composition of Maize Cultivars in Different Growing Groups

“…This result is partly consistent with a previous report (Amegbor et al, 2022). Yousaf et al (2021) showed the negative association between starch and fat content.…”

Impact of Heat Stress on Agro-Morphometric and Fiberrelated Traits in Indigenous Upland Cotton Genotypes Under Semi-Arid Conditions

“…Correlation coefficient analysis was adopted to investigate the relationship between different parameters of cotton genotypes under heat stress conditions. Correlation analysis is one of the most basic statistical approaches utilized by researchers to explore the association between different plant traits under different circumstances including heat stress Yousaf et al 2021a;Yousaf et al, 2021b;Riaz et al;Rahman et al, 2022).…”

“…For this, different statistical approaches could be used but multivariate analysis provides the best possible solution for the selection of genotypes. It is considered one of the best methods to evaluate crop genotypes worldwide under stressed and non-stressed conditions (Munir et al, 2020, Yousaf et al, 2021a, Rahmanet al, 2022. Therefore, multivariate modelbased approaches i.e., Principal component and cluster analysis were applied to screen cotton genotypes for their tolerance against high temperature.…”

Leveraging Multiomics Insights and Exploiting Wild Relatives’ Potential for Drought and Heat Tolerance in Maize

“…The optimal temperature for maize growth and development varies from stage to stage and during the light and dark hours. During daylight, it grows best between 25 and 33 °C, whereas during dark hours, 17–23 °C is required . However, mean temperature throughout the growing season is 20–22 °C.…”

“…During daylight, it grows best between 25 and 33 °C, whereas during dark hours, 17−23 °C is required. 35 However, mean temperature throughout the growing season is 20−22 °C. The optimum temperature for germination is slightly on the higher side, i.e., 25−28 °C.…”