| A comparative study of three selection procedures in
bread wheat I. SINGH, R.K. CHOWDHURY, I.S. PAWAR and S. SINGH Haryana Agricultural University Hisar 125004, India Several selection procedures (pedigree selection, bulk population breeding, single seed descent, mechanical mass selection, etc.) have been proposed for improving self-fertilized crops. However, only a few of these procedures have been used extensively in wheat. The knowledge about the relative efficiency of the different methods may greatly help the plant breeder in choosing a better method to be adopted in a particular crop. The information available on this aspect is little and controversial. Keeping these points in mind, an attempt has been made to compare the efficiency of pedigree selection, bulk breeding and single seed descent (SSD) methods in a three-way wheat cross. Materials and Methods The F2 generation of a three-way wheat cross (WH157 x T460-P-1200-5) was grown in two lots i.e. space planting and at commercial seed rate in 1982-83 at the research farm of Haryana Agricultural University, Hisar. The population grown for exercising pedigree selection was space planted. Ten per cent plants were visually selected on the basis of plant type, good tillering, ear characteristics and disease resistance from F2 generation and were grown as F3 progeny rows during 1983-84 crop season. Subsequently, superior plants were selected from F3 progeny rows and grown as F4 progeny rows during 1884-85 and finally 35 single plants were selected from the chosen progeny rows in F4 generation and grown as F5 progeny rows during 1985-86. Under bulk method, a random sample of seed was taken from F2 bulk plot grown during 1982-83 and advanced to F3 bulk during 1983-84. Subsequently, random sample of seed was taken from F3 bulk and grown as F4 bulk plots in space planting during 1984-85. Finally, a random sample of 35 plants was selected from space planted F4 bulk and grown as F5 progeny rows during 1985-86. In SSD procedure, one seed was taken from each healthy plant from F2 generation grown for pedigree selection during 1982-83. Seeds collected in this way were bulked to constitute F3 SSD, which was grown during 1983-84. Again, single seeds were collected from individual plants of F3 SSD population and grown as F4 SSD in space planting during 1984-85. Finally, a random sample of 35 plants was taken from space planted F4 SSD population and grown as F5 progeny rows during 1985-86. In this way, one hundred and five progenies (35 from each of the three selection procedures) were grown in a randomized block design with three replications in single row plots of 3m length having row to row distance of 23 cm and plant to plant distance of 10 cm during 1985-86. The data were recorded on five randomly selected competitive plants from each progeny rows per replication for days to heading, plant height, effective number of tillers, number of grains per spike, 1000-grain weight and grain yield per plant. The efficacy of the three selection procedures was compared on the basis of mean performance (top 25 lines), range, phenotypic coefficient of variation, genotypic coefficient of variation, heritability and genetic advance. All statistical parameters were computed using standard statistical procedures. The expected genetic advance at 5 per cent level of selection intensity was computed using standard procedures as suggested by Johnson, ROBINSON & COMSTOCK (1955). |
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