Phenotyping of sweet sorghum for tolerance to hydric stress through morphological characteristics

Abstract

This study was conducted to identify the sweetsorghum cultivars presenting higher tolerance todrought as well as to phenotypically discriminatethe root morphological characteristics of thosegenotypes for environments with water deficit.The cultivars (Rio, Ramada, BRS 501 andBRS 506) were subjected to two treatments(Environments). The first one was an environmentnamed unrestricted water (AI) -37.5 kPa, andthe second one, with hydric restriction, namedrestricted water (AR) with a matrix pressurelower than the with CPA treatment, that is, -375kPa. The difference between the ideal weight ofthe treatment and the weight observed in thevase, before being irrigated, when compared withan identical vase used in the treatments withoutthe plant, provided an evapotranspiration ofthe cultivar during the period. The roots wereanalyzed by the WinRhizo system, in orderto obtain the following characteristics understudy: length, volume, superficial area, projectedarea and root diameter. For all characteristicsunder evaluation, the variance analysis showedno interaction (P> 0.05) between genotypeand environment. Separately, no variationswere observed (P> 0.05) in the genotypes and environments evaluated for the characteristicsunder study, except the root diameter. Thus,it was observed that the diameter of the rootswere higher (P <0.05) when the plants weresubmitted to higher drought stress conditions(AIR). Findings indicate that the cultivars didnot present significantly different characteristicsin the contrasting environments, which probablyoccurred because they are very tolerant to theimposed stress, the phenological stage underevaluation study was too initial, or the stress hadlow intensity to generate different activities in thecultivars..

Keywords

• Sweet sorghum. Roots (Botany). Plants – Effect of drought.