PYRAMIDING OF GENES/QTLs FOR FUSARIUM WILT AND DROUGHT RELATED TRAITS THROUGH MARKER ASSISTED BACKCROSS BREEDING IN CHICKPEA (Cicer arietinum L.)
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Date
2015-04
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University of Agricultural Sciences Dharwad
Abstract
Chickpea (Cicer arietinum L.) is the most important grain legume in the arid and semi-arid regions of the world. Major biotic and abiotic constraints limiting chickpea production and productivity are Fusarium wilt and drought, respectively. Hence the present investigation was carried out to pyramid genes/QTLs for these two stresses in a single genotype with higher productivity. With this objective various populations viz., F2, F3, BC1F3, BC2F2 and BC2F3 were derived from a cross between ICC13124 and WR-315. Parent ICC13124 is drought tolerant and agronomically superior but susceptible to wilt, WR-315 is highly resistant to wilt whereas, susceptible to drought stress.
AB QTL approach was followed to construct map and to identify QTLs in BC2F2 population consisting of 144 families. Forty-nine polymorphic markers were mapped on 8 linkage groups covering 1323cM with an average marker density of 27cM. In total 94 QTLs were identified for 23 characters and 4 QTLs for Fusarium wilt race1A.
Considerably high variability was observed for most of the productivity related traits like plant height, number of branches, biological yield, number of pods and seeds per plant, hundred seed weight and seed yield in all the populations evaluated.
New drought tolerance index DPI was defined and validated in different populations and DPI alone can be used in isolating most productive and drought tolerant lines whereas combination of two or three indices is necessary in case of other drought tolerance indices.
Twenty four high yielding, wilt resistant and drought tolerant BC2F2 lines were selected based on foreground and background selections and these lines were selfed to fix introgressed segment in a homozygous condition and to get BC2F3 ILs. Out of 24 superior wilt resistant and drought tolerant ILs, five lines viz., BC2F3-6-4-2, BC2F3-14-3-9, BC2F3-15-5-8, BC2F3-15-3-4 and BC2F3-16-1-14 identified at ICRISAT were pyramided with three QTLs for Fusarium wilt race1A and also drought related QTLs. These lines can be directly released as varieties after selfing for 2-3 generations and testing in multilocation or can be registered as genetic stocks.
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