P. K. SinhaManigopa Chakrabarty2024-05-162024-05-161986https://krishikosh.egranth.ac.in/handle/1/5810209056Natural and gamma-ray induced variability’s for twelve quantitative characters were studied in 5 hulled and 6 hull less varieties of barley (Hordeum vulgare L.) and some of the 72 crosses between the hulled and hull-less types. The quantitative characters studied, were (1) germination percent, (ii) final survival percent, (111) heading date, (iv) days to 50% flowering. (v) plant height, (vi) number of tillers per plant, (vii) number of effective tillers per plant, (viii) length of mature spike, (1x) am length, (x) number of spikelets per spike, (xi) 1,000 grain weight and (x11) grain yield per plant. The studies revealed that the degree of phenotypic variability was different for different characters and was dependent upon the genotype and the generation of the population studied. Heritable and non-heritable components of variation were ascertained with the help of suitable genetic parameters such as, genetic co-efficient of variation, heritability (in broad sense) and expected genetic advance. Analysis of variance indicated that there were higher genotypic co-efficient of variation in treated parental and F2 populations than in the respective untreated ones for six characters viz., germination percent, final survival percent, heading date, days to 50% flowering, plant height and grain yield per plant. But between the two irradiated populations, parental population had higher genotypic co-efficient of variation than the F2 population. This indicates the scope of mutagen treatment of the parental materials in increasing variability for the above mentioned characters. For the remaining six characters, there were higher genotypic co-efficient of variation in normal (untreated) F2 populations as compared to the irradiated F2 population. But in case of parental types the genotypic co-efficient of variation were higher in the irradiated populations as compared to the normal (untreated) ones. This suggests that there is better scope of increasing variability’s for these characters through hybridization alone (i.e. in F₂ population) or by treating the parental seeds with mutagen without having recourse to hybridization. Heritability estimates and genetic advance also varied widely depending upon the characters, the generation as well as the genotype under study. It may, therefore be, concluded that in any breeding programme for yield improvement, one has to seek suitable methods for increasing the range of variability in the yield contributing characters. This in turn, would form a base from which selections can be made. To achieve this end, one can have recourse either to mutagen treated (induced) variability in the parental population itself or to inter varietal hybridization.EnglishThesis