In vitro and ex vitro Selection of Potato Plantlets for Resistance to Early Blight

Abstract

Reaction to the culture filtrate of Alternaria solani (Sorauer) was used as an indicator in an in vitro screening test to select lines with decreased field susceptibility to early blight from a population of 1000 putative mutants. Plantlets of cv. ÔDesire´e derived from irradiated callus of potato were inoculated in vitro with a culture filtrate of A. solani (Sorauer). Of the 45 lines selected and subsequently evaluated under conditions of natural infection in the greenhouse six showed lesser degrees of early blight infection than the cv. Desire´e control. The six lines selected in the greenhouse retained lower degrees of infection during 2 years of field trials.

Assessment on early blight of potato in order to compare the two methods<i> in vitro </i>using pathogenic fungi <i>Alternaria solani</i>

“…Mean comparison in vitro method (Table 4) showed that in droplet method Desiree cultivar had low resistance level, however in direct method Desiree cultivar had high level the symptoms of early blight in vitro with were taken 1 -3 days after inoculation that results is a similar too described by [6]. Culture filtrate was used in in vitro condition and caused leaf necrotic, were similar to those caused by infection through spores as was described by [9,10,13].…”

“…This study was conducted using factorial based on completely randomized design (CRD) with 3 replications. The test tubes were placed for 6 -7 days in a growth chamber at 20˚C -25˚C, with a photosynthetic photon flow density of 100 µE/m/s and a day length of 16 h [10]. During in vitro assay the A. solani symptoms appear 1 -3 days until 6 days.…”

“…Rodriguez et al showed that in vitro direct method is an effective in the evaluation of disease resistance of potatoes wave spots [10]. While Locke showed that drip into the glass, is a useful technique [14].…”

“…The droplet inoculation method has been used to evaluate early blight resistance components (O'Leary and Shoemaker, 1983). The direct method was described by [9,10]. Plantlets were inoculated in a 18 × 2 cm test tube, containing 5 ml of A. solani culture filtrate.…”

Screening of Potato Lines Including Department Genetic & National Plant Gene Bank of Iran for Resistance to Early Blight (<i>Alternaria. solani</i>) Using Culture Filtrate Produced by the Fungus

“…Evaluation of susceptibility or resistance exists in potato cultivars with some of these methods [20]. Evaluation of in vitro methods, e.g.…”