Mutants obtained by chronic gamma irradiation of soybean [Glycine Max (l.) Merrill]varieties

Soybean [Glycine max (L.) Merrill] is a wonder crop, containing about 20% oil and 40% high quality protein, having multiple uses such as food, fodder and industrial products. In Hungary in he last few years there has been a renewed interest in improving protein and oil content of the soybean crop. Selection for oil and/or protein content from segregating populations, derived from induced mutagenesis or hybridization, is known to be effective. Orf and Helms (1994) emphasized, that to fulfill demands of both sellers and purchasers, combined selection for yield components, yield, oil and/or protein content has to be carried out. For this purpose mutant soybean germplasm s were developed by pedigree method from a Carpathian-Ukrainian (KA) further more a Vietnamese (VL40) local variety adapted to Hungarian environmental conditions by 100-300 Gy chronic gamma irradiation. A function index was introduced to evaluate the genetic variability for the quality parameters and the most important agronomic traits. Chronic gamma irradiation increased the genetic variability of the oil content in the KA and of the protein content in the VL40 germplasm. Function index predicted up to 28% oil content in the KA mutant germplasm. Plants with 24.1 and 23.6% oil content were selected from the 150 Gy and the 100 Gy populations in the M4 generation. In the M5, progenies of a superior plant with 23.6% oil content were homozygous for this characteristics, while progenies of a superior plant with 24.1% oil content were segregating. Year can cause +-2.0-2.5% differences in the oil content of the seeds. Oil content had a moderate negative correlation with 1000-seed weight in both of the above mentioned generations .Seed samples with the highest oil content were analysed for fatty acid composition using gas-liquid chromatography. Their linoleic acid content ranged from 51.8 to 55.0%. Unfortunately, in M5 the linolenic acid content was higher than in M4, varying between 7.9% and 9.3%. The 200 Gy dose significantly increased the number of pods, the number of seeds and the yield per plant. The applied doses, except the 150 and the 200 Gy ones, significantly decreased the 1000-seed weight as compared to the control. The seed yield performance at two locations showed significant differences. Function index predicted up to 48% protein content in the VL40 mutant germplasm. Plants with 43.6% protein content were selected from the 250 Gy population in the M4 generation. Their progenies had 44.5% crude protein content in the seeds. Unfavourable years can cause 3.0-3.5% reduction in the protein content of the seeds.Taking into consideration the market value of soybeans today, it would seem that mutant soybean ines with about 40% protein content would provide the expected economic benefits for soybean producers??in addition, their lysine and methionine content is also favourable. Developing a mutant soybean variety with more than 40% protein content in the seeds and no farm-yield reduction would produce about a 800 kg/ha protein yield in Hungary, and in the case of a 10% farm-yield reduction, this figure would come to about a 720 kg/ha protein yield. Growing higher oil soybeans (23.6%), even with a loss of farm production yield, theoretically, farmers could achieve an oil yield of about 460 kg