Screening for Genetic Variability of self-compatibility and seedset in sunflower (Helianthus annuus L.) inbred lines

This study was conducted at Gezira Research Station Farm (GRSF), Agricultural Research Corporation, Sudan, in winter seasons 2008/2009 and 200912010 to estimate the genetic variability of self- compatibility and seed set in forty inbred lines of sunflower (Helianthus annuus L.). The experiments were arranged in a randomized complete block design with three replicates. The measured traits were days to 50% flowering, plant height, number of branches, head diameter, number of seeds per head, percentage of empty seeds, percentage of seed set, percentage of auto gamy, degree of self-compatibility, 100 seed weight, seed yield per head and oil content. Highly significant differences and genetic variability were observed among the genotypes for all studied traits in each season and their combined analysis indicating that there is sufficient variability available among the studied genotypes which could be used to improve the crop. Across the two seasons combined, self- compatibility ranged from 61 to 100%, with average value 93%. The highest percentage of self-compatibility was found in SL 18 and the lowest in SL21. Seed set ranged from 41 to 83 %, with average value of 67%. The highest seed set was found in SL7 while the lowest was in SLI8. The highest phenotypic and genotypic coefficients of variation (PCV and GCV) were observed for number of branches followed by seed yield per head, number of seed per head, percentage of empty seeds, head diameter and 100 seed weight. High values ( 60%) of broad sense heritability (square h B ) were recorded for most studied traits with the exception of percentage of auto gamy (36%), self- compatibility (45%) and 100 seed weight (50%), which showed moderate heritability. High genetic advance (as percentage of mean) was gained by all traits investigated. Therefore, selection will be effective to improve these traits. Oil content (from one season) showed high heritability and moderate genetic advance, whereas it has low PCV and GCV indicating a strong influence by the environment. From these results, the top five ranking genotypes for self- compatibility were SLI8, SL38, SL3, SL17, SL12 and SL8. Whereas, the best five genotypes for seed set were SL7, SL14, SL21, SL27 and SL31. These elite genotypes, with high values of self--compatibility and good seed set could be considered as a good starting material for hybrid production in the future