"MORPHOLOGICAL AND BIOCHEMICAL CHARACTERIZATION RELATED TO THE TESTING OF GENETIC PURITY OF COTTON HYBRIDS"
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Date
2003-07-29
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MAHATMA PHULE KRISHI VIDYAPEETH, RAHURl - 413 722, DIST. AHMEDNAGAR, MAHARASHTRA, INDIA
Abstract
The present investigations were undertaken with seven cotton hybrids viz., PKVHY-2, CAHH-468, JKHY-1, H-10, PHH-316, RHH-1394 and RHB-0387 and their parents during 2000-2002 at Cotton Improvement Project and Seed Testing Research Unit, MPKV, Rahuri. The objectives were to test the genetic purity of cotton by morphological and biochemical characterization, to identify the hybrid by marker characters, to know the inbreeding depression in F2 generation for its feasible use in commercial cultivation, to find the trend of mixture/adulteration in seed lots sold in the market and to test the genetic purity by RAPD. The morphological characteristics exhibited by different genotypes/hybrids studied indicated that, although some of the hybrids/genotypes have common morphological features in respect of some characters, they can be differentiated from each other on the basis of other specific characters. The hybrids PKVHY-2 and CAHH-468 could be identified by their stem and leaf hairiness, flower colour, petal spot, pollen colour, position of stigma and boll shape. The hybrid JKHY-1 could be identified by plant height, flower and pollen colour, boll shape and lint content. H-10 by its growth habit, boll shape and pollen colour. PHH-316 could be differentiated from others by its growth habit, petal and pollen colour and RHH-1394 by its flower colour, position of stigma and boll shape. RHB-0387 could be differentiated by plant height, leaf size, leaf colour, flower colour, petal spot, locules/boll, boll pitting and fuzz colour. The hybrids could also be distinguished by their morphological markers like seedling pigmentation, flower colour, pollen colour, petal spot, position of stigma, boll shape and fuzz colour. These markers were found useful for distinguishing hybrids from their parents. The F2 generation produced considerably low yields as compared to their F! hybrids. High inbreeding depression for both yield and fibre characters viz., yield/plant, bolls/plant, boll weight, monopodia/plant, sympodia/plant, ginning per cent, seed index, 2.5 % span length, micronaire, bundle strength, fibre quality index was observed in the F2 generation. The F2 plants also showed wide variation for yield and other growth characters and were interior to Fi thus limiting their feasibility to be used for commercial cultivation. Biochemical characterization of parent and hybrids revealed that the oil content in various genotypes ranged from 17.95 to 23.05 per cent, protein from 36.00 to 44.25 per cent while gossypol range from 0.344 to 0.888 per cent. Molecular characterization by RAPD, using 15 random primers showed that only three primers OPD-15, OPD-05 and OPA-10 showed polymorphism while other primers showed monomorphic amplification or did not show any amplification of the genomic DNA. Primer OPD-15 could be used to test the hybridity of CAHH-468. From the grow-out test, it was observed that the per cent off types in three market seed lots each of PKVHY-2 and H-10 were higher than minimum seed certification standard prescribed for certification (10 %). Significantly low germination and seedling vigour and higher ercentage of dead seed and abnormal seedlings were observed in market seed lots.
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