primary morphological screening of 698 grapevine genotypes to select drougth tolerant rootstocks

grapevine rootstocks are of the potential to increase cultivars, adaptation to different climates, soil types and a variety of unfavorable conditions. considering the existence of a rich grapevine germplasm in iran, it is possible to pick up vigorous genotypes and cultivars as drought tolerant rootstocks for commercial use due to their vast genetic potential. in this study, 698 fruitful genotypes from the collection of the national iranian grapes research station, takestan(qazvin province) were studied as based upon the characters considered in the grapes, descriptor with emphasis on vigor grape, descriptor related traits and some potent genotypes being selected within three distinct stages. the first stage of evaluation, that included leaf and branches, hair density traits, resulted in choosing 150 genotypes, further evaluated for trunk diameter and shoot length in three replications as the second stage. a third stage of evaluation was comprised of 17 morphological traits associated with drought tolerance, studied on the screened genotypes in field conditions at the national collection of grape varieties of iran. the final number of genotypes was decreased to 44, within medium screening, and with consideration of others, recognized drought tolerant genotypes. results indicated that there was not any correlation between trunk diameter and shoot length, and therefore shoot length could not be considered as an index of vigor and its related drought tolerance. there were significant positive vs. negative correlations between and among the studied traits, except for shoot length. kaj angur of bojnurd, sorkhak from quchan, siyah mamuli (ordinary black) of zarghan and ghalati of shiraz bore drought tolerance traits and were proposed as promising, but only after, undergoing further complementary experiments.