| Genetics of grain yield in relation to total biological
yield in Triticale R.K. BEHL and V.P. SlNGH Haryana Agricultural University Hisar - 125004, India The utility of harvest index as a selection criterion for effective improvement of grain yield, particularly in cereals, has been emphasized (DONALD & HUMBLlN 1976). Combining ability analysis is useful for the selection of parents to be involved in hybridization programme aimed at recombining favourable gene constellations scattered over different genotypes. This has particular relevance to Triticale because of its narrow gene pool, low floret fertility and harvest index and high biological yield. Present study deals with combining ability analysis for productivity traits in hexaploid Triticale. Materials and Methods Hexaploid Triticale lines selected on the basis of genetic divergence were crossed in line x tester design. Parental strains included 18 lines viz., 1. T24, 2. T103, 3. T125, 4. T130, 5. T134, 6. Tcl. 3, 7. TL-37, 8. TL-39, 9. TL-46. 10. TL-56, 11. UPT74364, 12. UPT74418 13. UPT74460, 14. UPT74536, 15. Arm-147, 16. Armadillo, 17. Koala and 18. Cinnamon and 4 testers, namely, 1. St69-1, 2. 6TA204, 3. TL-22 and 4. UPT73535. The patents and resultant 72 F1 hybrids were sown in randomized block design with three replications. Inter and intra row distances between two plants were 30 cm and 10 cm, respectively. Five plants from each replication were selected for recording observation on number of grains per spike, floret fertility (%), 1000 grain weight (g), biological yield per plant (g) and grain yield per plant (g). Harvest index was expressed as ratio of grain yield to total biological yield per plant (excluding roots). Mean values for all the characters were subjected to analysis of variance for combining ability as suggested by KEMPTHORNE (1957). Results and Discussion Analysis of variance for combining ability revealed highly significant differences among hybrids for all the characters. Further partitioning of mean squares into orthogonal contrasts indicated that differences due to females, males and female x male interactions were also significant. (Table 1). Thus sufficient variation existed in the material. Based on good gca effects and high per se performance (Table 2) few genotypes figured important. These were: Cinnamon and T130 for grain yield, harvest index, grains per spike and floret fertility; TL-39 and T134 for 1000 grain weight and biological yield; Armadillo and T125 for floret fertility and 1000 grain weight and UPT74535 for number of grains per spike, biological yield per plant and grain yield. Inclusion of such genotypes in population improvement programme following diallel selective mating (JENSEN 1970) or concurrent random mating and intermating in segregating generations followed by selection (JENSEN 1978) would maximize the chances of getting desirable recombinants for production attributes. |
| --> Next |