M 2 population was raised from M 1 seed developed from the intraspecific crosses (NIAB-78 x REBA-288) with male parent pollen irradiated at 10Gy of gamma rays. Different mutants having higher yield, early maturity, short internode, resistant to CLCuV disease etc. were selected. These mutants were evaluated for yield potential and other economic traits in different segregating generations in comparison to then standard cotton varieties. Out of these, the mutant PIM-76-8 consistently out-yielded all the prevalent standard cotton varieties/parents i.e. CIM-240, CIM-448, CIM-443, NIAB-78 and Reba-288. On the average it gave 28.2% higher yield than the standard cotton variety CIM-443 in the micro-yield trials conducted at NIAB during 1998-99. Further evaluation of mutant, PIM-76-8 is in progress and the results are encouraging.

Attempts were made to incorporate intraploid interpsecific gene(s) from Gossyium barbadense into G. hirsutum through DNA-mediated embryo transformation approach. G. barbadense DNA was injected into the styles/ovaries of G. hirsutum, 24 hours after self pollination. Two phenotypic types of plants i.e. transformed and G. hirsutum like were observed in D population. The transformed plants had clearcut variations in boll weight, yield and other quality traits confirmed to recipient parent. D transformations were also heritable and were transmitted to D generation. The transformed plants had better boll weight (4.9 gm), better fibre fineness (3.9 µg/in) and better fibre strength (101.0 TPPSI) compared to the boll weight (3.0 gms), fibre fineness (4.5 µg/in) and fibre strength (91.0 TPPSI) of G. hirsutum. The transformation efficiency for quantitative traits was about 20 % where as low for qualitative traits like flower petals with red spot (0.08 %). In the present studies transformed genotypes illustrated higher yield potential and better fibre quality than the recipient (G. hirsutum) parent.

The research studies were carried out to enhance the incorporation of G. arboreum and G. barbadense genes for disease resistance and quality traits respectively into G. hirsutum through DNA-mediated embryo transformation technique. The self fertilized flower/ovaries of the recipient were injected with the donors DNA solutions irradiated at low doses ie. 2.5 Gy of gamma rays. The result of D 1 and D 2 generation revealed the enhanced incorporation and preservation of the donor parent traits into the recipient. Higher percentage of CLCV resistant plants and plants with increased quality traits were obtained from the irradiation DNA treatments. The transformed genotypes had higher yield and other economic traits better as compared to recipient. Moreover the expression of qualitative traits of the donor i.e. petal spot, pollen colour and flower colours were observed in D 2 generation.

Fifty-three different indigenous genotypes of cotton screened for CLCuV disease and other traits were found not to be possessing good combination of desirable traits alongwith resistance to cotton leaf curl virus disease. It was noted that the genotypes carrying some identified novel genes of economic value can be manipulated and utilized for the synthesis of the requisite desirable genotypes which would better suit to the varying climatic conditions of the country. Out of the selected genotypes, Pak-3, Pak-7, Pak-13, Pak-28 and Pak-50 are being improved for specific lacking characters i.e. yield, earliness etc. to develop desirable genotypes to achieve the desired objectives. While other promising genotypes viz., Pak-23, Pak-25, Pak-27, Pak-48 and Pak-38 possessing some desirable traits but are susceptible to CLCuV disease are being utilized as valuable genepool in the project as well in our cross breeding programme. Moreover the existing germplasm resources will be further enhanced when the germplasm from Kazakhstan will be added to the existing one after the exchange with the local germplasm. Progress made, future strategies/problems, efforts relating to the project are being described and discussed.

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