Genetic Analysis of Root-Knot Nematode Resistance in Cotton

R.L. Shepherd


 
ABSTRACT

Root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, egg Production on six genetic populations of cotton, Gossypium hirsutum L., was investigated. The genetic populations were root-knot resistant breeding line Auburn 634 RNR, root-knot susceptible M-8, a doubled haploid of 'Deltapine 14', their F1 and F2 hybrids and the reciprocal F1 backcrosses to the parents. An analysis of generation means indicated that additive gene action and dominance were both significant for conferring resistance to root-knot nematode reproduction. No epistatic effects were found. Additive gene action was 4 times more important than dominance in determining inheritance of resistance. This indicates that steady progress can be made during each generation of selection for root-knot resistance. Dominance of resistance was indicated when only 13 to 15% as many root-knot eggs were produced on F1s from crosses between resistant and susceptible parents as were produced on the susceptible parents. This indicates that hybrid cotton with one resistant parent should reduce root-knot reproduction 85 to 87% compared with reproduction on susceptible cultivars.



Reprinted from 1986 Proceedings: Beltwide Cotton Production Research Conferences pg. 502
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998