Application of stress susceptibility index for drought tolerance screening of tomato populations

Abstract

Investigation comprised 41 tomato genotypes originating from the population of domestic and domesticated genotypes collected in Serbia and belonging to the tomato collection of the Institute of Vegetable Crop Science, Smederevska Palanka. The aim of collection screening was to choose the genotypes tolerant to drought during plant intensive growth stage, whereby the process of selection would set out to obtain the recombinant genotypes for this abiotic factor. The screening criteria were established for genotype divergence in plant height and shoot-root ratio under conditions of optimal irrigation regime and drought. Divergence was estimated using cluster analysis with Euclidean distance as a measure of distance, with a complete gene attachment to grouping. Drought tolerance is expressed by the stress susceptibility index (SSI). Various results were obtained based on the screening of genotypes grown under optimal and dry conditions. As a measure of stress susceptibility, based on SSI, genotypes having different drought tolerance level were determined. On the grounds of the analyses carried out, 10 genotypes were segregated (G102, G104, G107, G109, G110, G119, G125, G126, G128 and G141) to represent a basis to obtain the recombinant genotypes and to initiate the selection for drought resistance.

Ispitivanje je izvršeno na 41genotipu paradajza poreklom iz populacije domaćih i odomaćenih genotipova prikupljenih iz Srbije, a pripadaju kolekciji paradajza Instituta za povrtarstvo u Smederevskoj Palanci. Skrining kolekcije imao je za cilj da se izvrši izbor genotipova tolerantnih na sušu u vegetativnoj fazi intenzivnog porasta biljaka, čime bi se započeo program selekcije na dobijanje rekombinovanih genotipova prema ovom abiotskom faktoru. Kriterijumi za skrining bili su divergentnost genotipova za visinu biljke i odnos izdanak/koren u uslovima: optimalnog režima navodnjavanja i suše. Za ocenu divergentnosti korišćena je klaster analiza sa Euklidovom distancom kao merom udaljenosti, sa kompletnom vezanošću gena za formiranje grupa. Tolerancija na sušu izražena je indeksom osetljivosti na stres (SSI-stress susceptibility index). Različiti rezultati su dobijeni na osnovu skrininga genotipova koji su gajeni u optimalnim uslovima i u suši. Kao mera osetljivosti na stres prema indeksu osetljivosti definisani su genotipovi sa različitim nivoom tolerancije na sušu. Na osnovu izvedenih analiza izdvojeno je 10 genotipova (G102, G104, G107, G109, G110, G119, G125, G126, G128 i G141) koji će predstavljati bazu za dobijanje rekombinovanih genotipova i početak selekcije na otpornost na sušu.