Author : M. Afzal Arain; M. Ahmad; K.A. Siddiqui

Summary : Abstract: Use of induced mutations in plant breeding has become a profitable approach for the improvement of field crops. Some of these mutant varieties have been grown on large areas and have contributed significantly to the national economy. Triticum aestivum L. being self-pollinated species has remained one of the important crops among cereals for mutagenic studies. Quite a large number of varieties with improved agronomic traits have been developed through mutagenesis. At Nuclear Institute of Agriculture Tando Jam, genetic improvement of wheat through mutation breeding in combination with conventional breeding methods was started in 1972. Both physical (gamma rays and fast neutrons) and chemical mutagenesis (ethyl methane sulphonate and sodiuk azide) were used alone and in combinations for the treatment of seeds. Selection in M2 was mainly done on traits of agronomic significance. Mutants confirming in M3 generation and those showing phenotypic stability were evaluated in M4 and subsequent generations. Only productive mutants were promoted in zonal and national yield trials covering different ecological niches. Mutants with marker characters were included in the germplasm. From the elite material after passing through different trials, three mutant varieties were evolved and released in the Province of Sindh for general cultivation. The variety Jauhar 78 was evolved through fast neutron treatment. In addition to its higher grain yield and wide adaptability, possessed amber grain colour, shattering resistance and uniformity. Another variety Soghat 90 selected from the mutated population of sodium azide combined both high grain and biomass yield in a single cultivar. Besides higher yield, this mutant cultivar possessed higher protein as well as lysine content. This cultivar also possessed tolerance to leaf rust. Kiran 95, a product of mutagenesis and hybridization is a leaf rust resistant high yielding cultivar. The cultivation of these varieties in the Province of Sindh has significantly added an additional income of 87.1 US million dollars to the farmers. However, it was noted that the wheat cultivars developed through conventional breeding (Sarsabz and Sind 81) by Wheat Breeding Group at NIA, Tando Jam were also equally productive and rewarding.