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Transfer of cry 1ac and cry2aa for Pod Borer Resistance Into Wilt Resistant Chickpea (Cicer Arietinum l.) Variety Sa-1 Through Marker Assisted Ackcrossing

By: Contributor(s): Material type: TextTextLanguage: English Publication details: Dharwad University of Agricultural Sciences, Dharwad 2024Edition: P hd (Agri)Description: 115 32 CmsDDC classification:
  • 630.2748 KAN
Summary: Chickpea (Cicer arietinum L.) the major pulse crop of both India and World. It is self-pollinated crop. Chickpea is rich source of proteins, fibres and minerals. Pod borer and Fusarium wilt are the major problems affecting chickpea productivity. Hence the crop demands combining of both wilt and pod borer resistance. With the availability of Bt events and wilt resistant variety it was planned to combine both the traits in chickpea using marker assisted breeding. In the present study the cross SA-1 x BS 72C2(cry2Aa) 62,15 and 62 BC2F2, BC1F3 and F4 plants generated respectively, which were PCR positive for cry2Aa and wilt resistance(linked with QTL foc4).From the cross SA-1 x BS 100B (cry1Ac) 2 and 3 BC2F2 and BC1F3 plants generated which were PCR positive for cry2Aa and wilt resistance (linked with QTL foc4).About 27 and 40 BC1F3and F4 plants of the cross SA-1 x BS 72C2(cry2Aa) were raised on sick pot, among these 7 and 16 plant expressed wilt resistance in sick pot and these plants were PCR positive for both cry and wilt resistance. The Cry protein expression studied in the segregating generation of both crosses. After screening through Bt immune blot strips, the Cry protein expression confirmed through qualitative ELISA. Using quantitative ELISA the Cry protein was estimated in segregating populations. The average Cry2Aa protein recorded in segregating generation was 10.18 μg/gm and in transgenic event BS 72C2 it was 10.34 μg/gm. In case of Cry1Ac the mean protein estimated in segregating population was 12.57 μg/gm and in transgenic event 12.44 μg/gm was recorded. Insect bioassays carried out in both plants carrying cry2Aa and cry1Ac gene and it was recorded up to 95 % mortality in both plants. Hence, it was proved that cry2Aa and cry1Ac genes have same effect on pod borer. Recurrent parent genome recovery was studied in BC2F2 and BC1F3 generation plants in both crosses. Only in few plants recurrent genome recovery about 83-90 % was recorded. It may be due to use of less number of SSR markers. Per se performances of segregating populations from both crosses were studied. It was found that the segregating populations were significantly higher than commercial SA-1 variety with respect to height, primary, secondary branches, pods per plant and yield per plant it was observed 40-50 % increased yield in segregating populations over the commercial SA-1 variety. Hence, the segregating population generated from the present study were PCR positive for both pod borer and wilt disease and further cry gene expression was studied through ELISA and insect bioassay. The wilt resistance had been validated through raising on artificial sick pot. It can be concluded that apart from wilt and pod borer resistance the segregating population showed high yield potential. The generated genetic resources with combination of cry1Ac and cry2Aa gene stacking events could be studied.
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THESIS University of Agricultural Sciences, Dharwad 630.2748/KAN 1 Available T14158

Chickpea (Cicer arietinum L.) the major pulse crop of both India and World. It is self-pollinated crop. Chickpea is rich source of proteins, fibres and minerals. Pod borer and Fusarium wilt are the major problems affecting chickpea productivity. Hence the crop demands combining of both wilt and pod borer resistance. With the availability of Bt events and wilt resistant variety it was planned to combine both the traits in chickpea using marker assisted breeding. In the present study the cross SA-1 x BS 72C2(cry2Aa) 62,15 and 62 BC2F2, BC1F3 and F4 plants generated respectively, which were PCR positive for cry2Aa and wilt resistance(linked with QTL foc4).From the cross SA-1 x BS 100B (cry1Ac) 2 and 3 BC2F2 and BC1F3 plants generated which were PCR positive for cry2Aa and wilt resistance (linked with QTL foc4).About 27 and 40 BC1F3and F4 plants of the cross SA-1 x BS 72C2(cry2Aa) were raised on sick pot, among these 7 and 16 plant expressed wilt resistance in sick pot and these plants were PCR positive for both cry and wilt resistance. The Cry protein expression studied in the segregating generation of both crosses. After screening through Bt immune blot strips, the Cry protein expression confirmed through qualitative ELISA. Using quantitative ELISA the Cry protein was estimated in segregating populations. The average Cry2Aa protein recorded in segregating generation was 10.18 μg/gm and in transgenic event BS 72C2 it was 10.34 μg/gm. In case of Cry1Ac the mean protein estimated in segregating population was 12.57 μg/gm and in transgenic event 12.44 μg/gm was recorded. Insect bioassays carried out in both plants carrying cry2Aa and cry1Ac gene and it was recorded up to 95 % mortality in both plants. Hence, it was proved that cry2Aa and cry1Ac genes have same effect on pod borer. Recurrent parent genome recovery was studied in BC2F2 and BC1F3 generation plants in both crosses. Only in few plants recurrent genome recovery about 83-90 % was recorded. It may be due to use of less number of SSR markers. Per se performances of segregating populations from both crosses were studied. It was found that the segregating populations were significantly higher than commercial SA-1 variety with respect to height, primary, secondary branches, pods per plant and yield per plant it was observed 40-50 % increased yield in segregating populations over the commercial SA-1 variety. Hence, the segregating population generated from the present study were PCR positive for both pod borer and wilt disease and further cry gene expression was studied through ELISA and insect bioassay. The wilt resistance had been validated through raising on artificial sick pot. It can be concluded that apart from wilt and pod borer resistance the segregating population showed high yield potential. The generated genetic resources with combination of cry1Ac and cry2Aa gene stacking events could be studied.

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