Browsing by Author "SOMASHEKHAR"
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ThesisItem Open Access GENETIC STUDIES ON RECIPROCAL SELECTION FOR COMBINING ABILITY TO IMPROVE HYBRID PERFORMANCE IN COTTON (Gossypium hirsutum L.)(University of Agricultural Sciences GKVK, Banglore, 2007-08-30) SOMASHEKHAR; S.A PATILHybrid breeding programmes in eross pollinated erops like maize are supported by various schemes for improving combining ability by handling combining ability as a trait. By utilizing such scheme genetically diverse lines are developed, which when used, give rise to superior hybrid combinations, such method can be employed in cotton. The experimental material of this study was constituted by a set of four hirsutum varietal (parental) lines namely RAH 10 (A), RAH 100 (B), RAH20 (C) and RAH200 (D) forming two diverse single (RAHH102 (A X B) and RAHH136 (C x D)) crosses which are found to be veiy diverse from each other based on predicted double eross performance. Twenty six random F4 lines derived from these two single crosses were selected for use in assessing the variability for combining ability. These lines are crossed with three common testers viz., AACHH1065 (T3), 435308 (T4) and ZCH- 21045 (T5). Another two different testers were used as uncommon/reciprocal testers where RAHH136 (Ti) hybrid serves as a tester for evaluating F4 lines of RAHH102 lines and vice versa te., RAHH102 (T2) hybrid serves as a tester for testing combining ability of F4 lines of RAHH136 lines. The magnitude of variability for combining ability was assessed in terms of range, variance, coeflieient of variance and mean seed cotton yield of these derived Fis (26 dFis per tester) in comparison with straight crosses (crosses of parental lines A, B, C and D with tester concerned) and commercial check. By comparing dFis with superior straight crosses, the magnitude of transgressive segregation for combining ability was determined. Efficiency of testers were also determined based on the mean and variances of the derived Fis. Based on this 435308 (T4) was found to be most efficient in distinguishing the F4 lines of the both crosses, A sizeable portion of derived Fis was significantly superior over commercial check. Among F4 lines R-2 (102) (of RAHH 102) and R-5 (136) (of RAHH 136) lines showed highest improvement in combining ability for seed cotton yield and with regard to fibre properties R-1 (136) and R-6 (102) are the potential combiners. Based on weighted per cent gea method R-11 (102), R-18 (102), 1^21 (136) and R-3 (136) F4 lines were found to be potential combiners with higher pooled scores. The SCA variance for seed cotton yield- was high confirming the role of non-additivity including dominance in governing the expression of seed cotton yield. This also confirms the role of dominant favourable alleles in influencing the seed cotton yield. The combining ability status of most productive crosses in this study helped in drawing the inference about handling the best crosses. Apart from sea, gea effects also contributed to superiority of these crosses justifying the emphasis on developing these Fis into commercial hybrids. In general, the correlation between genetic distances through RAPD among parents and the heterosis shown by their hybrids was non-signifieant may be because the molecular markers used to calculate genetic distances are not linked to the genes controlling seed cotton yield.ThesisItem Open Access GENETIC STUDIES ON RECIPROCAL SELECTION FOR COMBINING ABILITY TO IMPROVE HYBRID PERFORMANCE IN COTTON (Gossypium hirsutum L.)(University of Agricultural Sciences GKVK, Banglore, 2007-08-30) SOMASHEKHAR; S.A PATILNo AbstractThesisItem Open Access STUDIES ON THE QUALITY OF IRRIGATION WATER WITH REFERENCE TO SOIL CHARACTERISTICS IN JUNNAR TAHSIL OF PUNE DISTRICT(MAHATMA PHULE KRISHI VIDYAPEETH, RAHURI- 413 722, DIST. AHMEDNAGAR, MAHARASHTRA STATE, (INDIA), 01-12-04) SOMASHEKHAR; Patil, Dr.Bhardas.P; Surve, Dr.S.P; Shinde, Dr.D.B; Tuse, Prof. B.PThe objective of the present investigation was to Study the quality parameters of irrigation water and its influence on soil chemical characteristics and temporal variation of water and soil properties from Junnar tahsil of Pune district. The water and soil samples were collected during month of June 2003, October 2003 and February, 2004 and analysed for their different chemical properties. Among the quality parameters of irrigation waters, pH of all water samples was found alkaline in nature. The electrical conductance showed, about 11.78 per cent samples were found good category and 70.58 per cent samples were found permissible and only 17.64 per cent samples were found doubtful category for crop production. Among the cations Na+ was predominant cation followed by Ca"^, Na+, K+ whereas in anionic concentration, it was observed that SO4" was predominant followed by CI" and HC03" and CO3" were in traces. As per the SAR and RSC ratings these irrigation water were found to be suitable for crop production. As per the temporal variation in irrigation water is concerned, pH showed highest value in October month whereas EC was highest in June and lowest in October. The trend of total cations and anions were as similar to EC. The temporal variations in pH and EC of soil showed no much variation. The cation concentration was highest in the month of June and was lowest in the month of October. In irrigated soils, pH of irrigation water showed significantly positive correlation with soil pH, Ca2+, Mg+2, and Na+ and trends were similar for EC of water also. The exchangeable Ca of irrigation water had positive influence on soil pH, EC, soil Ca2+, Mg+2, and Na+. The Mg2+ and Na+ also showed significant correlation with soil pH, EC, Ca2+, Mg+2. RSC showed significantly negative correlation with all soil chemical properties.