GENETIC STUDIES ON HEADING, MATURITY AND YIELD AND ITS COMPONENTS FOR LATF SOWING CONDITIONS IN WHEAT (T. AESTIVUM L) | ||
| Egyptian Journal of Agricultural Research | ||
| Article 14, Volume 84, Issue 2, June 2006, Pages 445-462 PDF (4.51 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejar.2006.230337 | ||
| Author | ||
| NADYA A. R. ABDEL-NOUR | ||
| Field Crops Research Institute, Agricultural Research Center, Giza, Egypt | ||
| Abstract | ||
| An understanding of genetic analysis of earliness components is needed to develop early lines. Six bread wheat (Triticum aestivum L.) genotypes differing in earliness were crossed in all possible combinations exduding reciprocals in 2003/2004 season. In 2004/2005 growing season, parents and FIS were planted on Jan 5th and grown in a field experiment in EI-Giza Experimental Farm Agricultural Reasearch Center. The Randomized Complete Blocks Design with three replications was used. Days to heading, days to anthesis, days to maturity, grain filling period and grain filling rate (earliness components), plant height, number of spikes per plant, number of kernels per spike, 100-Kernel weight, total plant weight, grain yield per plant, straw yield per plant and harvest index were recorded. The FiS and 15 wheat crosses and their respective parents were statistically analyzed to detect some information on the genetic effects governing the studied characters. The obtained results showed that positive heterosis values were detected for different studied characters. The mean squares of genotypes, parents and crosses were highly significant for all studied traits. The variances associated with general and specific combining ability reached the level of significant for all studied characters. GCA variance values were two times higher than the SCA variance ones for days to heading, days to anthesis, days to maturity, plant height and 1000-kernel weight, suggesting the predominant role for additive type of gene action. Moreover, the parents P2 (Gemmiza 10) and P4 (Line 4) were the best combiners for grain filling rate and grain yield. Meanwhile, significant SCA effects for grain filing rate, grain yield, straw yield and total plant weight were found in the crosses between P1 X P3, P1 X P6, P2 X P3, P2 X P4 and P4 X P5. On the other hand, P2 X P6 showed significant SCA effect for grain filling rate and grain yield. The additive variance (D) effects were significant for all studied characters except for grain filling rate, 100-kernel weight, grain yield and total plant weight. The relative proportions of variance due to non-additive effects were significant for all characters except for 100-kernel weight and were greater of most characters in magnitude than the additive component (D). Overall dominance effect of heterozygous loci (h2) was significant in most traits, which indicating that the effect of dominance was due to heterozygosity. Over dominance effect was observed for all studied characters except for days to heading and days to anthesis. Values of H2/4H1 analysis being less than 0.25 indicated asymmetric distribution of positive and negative allels among parents for all characters except for plant height, 100-kernel weight, grain yield and total plant weight. On the other hand, low values for narrow sense heritability for most studied characters• were observed, reflecting that most of the genetic variance were due to non-obtained genetic effects. | ||
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