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University of Agricultural Sciences, Dharwad

The University of Agricultural Sciences, Dharwad was established on October 1, 1986. The University has 5 Colleges, 27 Research Stations, 6 Agriculture Extension Education Centers, 6 Krishi Vigyan Kendras and ATIC. The University has its jurisdiction over 7 districts namely Bagalkot, Belgaum, Bijapur, Dharwad, Gadag, Haveri, and Uttar Kannada in northern Karnataka. Greater diversity exists in soil types, climate, topography cropping and farming situations. The jurisdiction includes dry-farming to heavy rainfall and irrigated area. Important crops of the region include sorghum, cotton, rice, pulses, chilli, sugarcane, groundnut, sunflower, wheat, safflower etc. The region is also known for many horticultural crops. Considerable progress has been registered in the field of education, research and extension from this University.

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20072
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Start date: 2000 × End date: 2009 × Author: D.Ratna Babu ×
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    ThesisItemOpen Access
    Molecular evidence to in vitro pollen bioassay for wilt resistance in chickpea
    (UAS, Dharwad, 2007) D.Ratna Babu; R.L.Ravi Kumar
    Fusarium wilt caused by Fusarium oxysporum is the major biotic factor limiting chickpea productivity in India. Despite the availability of stable resistance sources, development of resistant varieties is hindered due to lack of effective screening techniques. Conventional screening in sick plots is tedious and time consuming. Alternatively in vitro pollen bioassay is emerging as an effective screening technique. The pollen grains of sixteen diverse genotypes were tested for in vitro pollen tube growth by adding different concentrations of fusaric acid to pollen germination medium. The toxin inhibit pollen tube growth and genotypes showed significant variation for the concentration of toxin to inhibit 50 per cent pollen tube growth. The genotypes were phenotyped for wilt reaction using the in vivo seedling reaction to fusaric acid. The genotypes were also tested for their wilt reaction using established molecular markers. The genotypes which were categorized as wilt resistant using molecular markers and in vivo seedling reaction were also resistant under in vitro pollen bioassay requiring higher toxin concentration for pollen tube inhibition. Further, 50 recombinant inbred lines of cross JG-62 (H1H1H2H2) x WR-315 (h1h1h2h2) were analyzed for their wilt reaction using in vitro pollen bioassay. RILs showed significant variation for the toxin concentration to inhibit pollen growth. The RILs were classified into resistant, susceptible late wilters and susceptible early wilters using molecular markers. The resistant RILs required significantly higher toxin concentration for pollen tube growth inhibition, followed by late wilters and early wilters. The efficiency of pollen bioassay in selecting resistant segregating was studied in F5 generation of BG-256 x WR-315. The resistant F5 progenies selected based on pollen bioassay produced resistant F6 progenies. The present study involving DNA markers linked to wilt resistance loci, three different sets of genetic material and experiments performed over a period of time clearly showed that the selection of genotypes for Fusarium wilt resistance based on pollen bioassay is as reliable as marker assisted selection and/or sporophytic selection of not more.
  • Thumbnail Image
    ThesisItemOpen Access
    Molecular evidence to in vitro pollen bioassay for wilt resistance in chickpea
    (UAS Dharwad, 2007) D.Ratna Babu; R.L.Ravi Kumar
    Fusarium wilt caused by Fusarium oxysporum is the major biotic factor limiting chickpea productivity in India. Despite the availability of stable resistance sources, development of resistant varieties is hindered due to lack of effective screening techniques. Conventional screening in sick plots is tedious and time consuming. Alternatively in vitro pollen bioassay is emerging as an effective screening technique. The pollen grains of sixteen diverse genotypes were tested for in vitro pollen tube growth by adding different concentrations of fusaric acid to pollen germination medium. The toxin inhibit pollen tube growth and genotypes showed significant variation for the concentration of toxin to inhibit 50 per cent pollen tube growth. The genotypes were phenotyped for wilt reaction using the in vivo seedling reaction to fusaric acid. The genotypes were also tested for their wilt reaction using established molecular markers. The genotypes which were categorized as wilt resistant using molecular markers and in vivo seedling reaction were also resistant under in vitro pollen bioassay requiring higher toxin concentration for pollen tube inhibition. Further, 50 recombinant inbred lines of cross JG-62 (H1H1H2H2) x WR-315 (h1h1h2h2) were analyzed for their wilt reaction using in vitro pollen bioassay. RILs showed significant variation for the toxin concentration to inhibit pollen growth. The RILs were classified into resistant, susceptible late wilters and susceptible early wilters using molecular markers. The resistant RILs required significantly higher toxin concentration for pollen tube growth inhibition, followed by late wilters and early wilters. The efficiency of pollen bioassay in selecting resistant segregating was studied in F5 generation of BG-256 x WR-315. The resistant F5 progenies selected based on pollen bioassay produced resistant F6 progenies. The present study involving DNA markers linked to wilt resistance loci, three different sets of genetic material and experiments performed over a period of time clearly showed that the selection of genotypes for Fusarium wilt resistance based on pollen bioassay is as reliable as marker assisted selection and/or sporophytic selection of not more.