Characterization for Drought Tolerance and Physiological Efficiency in Novel Cytoplasmic Male Sterile Sources of Sunflower (Helianthus annuus L.)

Abstract

AbstractSunflower is sensitive to drought and its hybrids have a limited cytoplasmic diversity. The wild cytoplasmic sources of sunflower are not well exploited to their potential for drought tolerance and hybrid development. In this respect, we carried out a Line x Tester based genetic study using 19 sunflower genotypes representing, 13 cytoplasmic male sterile (CMS) lines from wild and conventional sources, 2 maintainer lines, and 4 restorer lines. The CMS and maintainer lines were crossed with restorer lines to develop sixty one-way F1 hybrids. The parents and their hybrids were evaluated under two water regimes viz., normal irrigated and water stress. A total of twelve important plant descriptors were studied over a period of two years. The significant differences were observed between parents and hybrids in both water regimes. Hybrids were higher in average values for all the descriptors than parents. The role of female parent was more prominent in the expression of traits in hybrids as compared to male parents. The CMS sources varied significantly regarding seed yield per plant and other physiological traits. Proline content was three times higher in parents and their hybrids under water stress, and it was not correlated with any other descriptor. Accession CMS-PKU-2A was identified as the best general combiner for leaf area and specific leaf weight. Whereas, CMS-234A was the best general combiner for biological yield and photosynthetic efficiency under both the conditions. The cross combinations CMS-ARG-2A x RCR-8297, CMS-234A x P124R, and CMS-38A x P124R were found significant for biological yield, seed yield and oil content under both environments. Overall, this study provides useful information about the cytoplasmic effects on important sunflower traits and drought stress tolerance when used in the different combinations.