AN INNOVATIVE TECHNIQUE FOR DISEASE RESISTANCE BREEDING: GAMETOPHYTIC APPROACH

Breeding for disease resistance is an important program in most of the cultivated crop plants. The large number of genes governing resistance invariably leads to handling large plant populations, consuming large areas and much time, besides limiting the probability of recovering the desired type. As an alternate, the present innovative technique was developed wherein gametes with desired alleles are selected in their haploid and unmasked condition. Easy handling as well as the possibility of handling a large gametophytic population in a small area and in short time periods using this innovative technique enhances the probability of recovering the desired genotype. Dianthus chinensis was selected as a model system to work out the strategy to develop lines resistant to Fusarium oxysporum f.sp. dianthi. Stigmas of flowers at receptive stage were pretreated with culture filtrate of F. oxysporum f.sp. dianthi. Pollination was attempted on pretreated stigmas as well as on untreated stigmas, resulting in progeny from selected pollen (PS) and progeny from unselected pollen (PUS) respectively. Artificial screening was done by incubating plants from both PS and PUS in culture filtrate. Results clearly indicated PS to be more tolerant to fusarium compared to PUS. Observations of visual wilting were further confirmed by measuring water holding potential as well as leakage of solutes.

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