| Evaluation of wheat mutants for yield and yield components
A.S. LARIK Department of Botany and Plant Breeding, sind Agricultural University, Tandojam, Pakistan Introduction Bread wheat; Triticum aestivum L. (2n=6x=42=AABBDD) being a polyploid, offers many opportunities of exploitation of mutations, recombinations and of increasing genetic variability in quantitatively inherited characters (SIDDIQUI, 1972; LARIK, 1975a, b). The presence of many triplicated and duplicated loci in wheat (SEARS, 1969) allows a large number of induced changes to be preserved and transmitted to the next generation. Also, with the advent of so-called green revolution interest in the induction of directed changes has considerably increased for redesigning ideotypes suitable for various agricultural environments. Induced mutations are also useful when it is desired to improve one or two easily identifiable characters in an otherwise well adopted variety (SIGURBJORNSSON, 1970). In breeding programme, estimates of heritability, genetic advance and genotypic variance provide guideline for developing an appropriate variety (LARIK, 1978). The present paper is concerned with an evaluation of phenotypically stable wheat mutants isolated from one locally bred cultivar and two cultivars of Mexican origin. Such evaluations are important for studying the spectrum and magnitude of change and for directing the induced mutations in a breeding programme. Material and Methods The material originated from different doses of gamma rays (20, 25 and 35 kR) and ethyle methane sulphonate (EMS) of varieties C-591 (locally bred), Nayab and Indus-66 (Mexican origin) of bread wheat Triticum aestivum L. Phenotypically stable mutants were evaluated for yield and yield components in M9 generation grown in the field in Tandojam during Rabi 1977-78. The seeds of these genotypes were procured from the Department of Botany and Plant Breeding, Sind Agricultural University, Tandojam, Pakistan. Homogeneous seed of mutants and cultivars was drilled in single rows each 3.1 m long with 30.5 cm interrow distance with path ways 1.0 m wide between blocks of a plot in randomized block design with four replications. After maturity 30 cm at each end of a plot was removed and remaining plot of 2.5 m was harvested and the weight of clean grain was recorded in g/plot. Observations were recorded on 5 randomly selected plants from each row for yield components. Thus 50 plants were studied from each mutant genotype and cultivars respectively. The mean values for the mutant population for each character were compared with the control mean by using t tests. |
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