Evaluation of Root Characteristics in Grain Sorghum¹

Abstract

Breeding for drought resistance has been limited by the lack of a simple method of screening. Observations in the field cannot be made regularly, nor can the condition be repeated. A laboratory method of testing for drought resistance was needed. To investigate techniques, 10 cultivars of sorghum, Sorghum bicolor (L.) Moench, were planted in washed sand in plastic plots in a growth chamber. Five plants in each pot were fed a nutrient solution for 3 weeks. When they were harvested, wet root weight, root length, root volume, and root/shoot ratio were determined. The purpose of this study was to evaluate the root characteristics among 10 sorghum cultivars known to vary for drought resistance. Significant varietal differences for all characters were found. In general the most drought‐resistant cultivars had heavier root weight, greater root volume, and higher root/shoot ratios. This technique shows promise for identifying drought‐resistant lines, but it involved a considerable amount of time and labor. Root weight would probably be the most indicative and easiest characteristic to determine.

Evaluation of morphological characteristics in Venezuelan maize (Zea mays L.) genotypes under drought stress

“…Thus, root dry weight could be used to predict yield under drought stress. In grain sorghum, root weight was identified as the best and easiest characteristic to determine drought-tolerance plants (NOUR et al, 1978).…”

Stay-green quantitative trait loci's effects on water extraction, transpiration efficiency and seed yield depend on recipient parent background

“…For instance, several studies have shown genotypic variations for rooting traits in genotypes contrasting for drought tolerance (Blum et al, 1977;Abd-Ellatif et al, 1978;Jordan et al, 1979;Vadez et al, 2007a). Yet, these studies did not resolve how particular root traits would contribute to water extraction, especially during grain filling, which could link with the expression of a stay-green phenotype.…”

Crescimento do sistema radicular e da parte aérea em plantas jovens de cafeeiros

“…Também observações de campo têm evidenciado esse aspecto do 'Catuaí'. Talvez a maior relação raiz/ parte aérea deste último seja um fator que favoreça sua melhor reação à deficiência hídrica em condições de campo, como ocorre em azálea (4,5,14,19).…”

“…Na avaliação feita aos 22 meses, a relação entre o peso seco de raízes laterais e da parte aérea do 'Catuaí' foi semelhante ao do 'Guarini' e superior à dos demais cultivares examinados. Maior proporção de raízes em relação à parte aérea tem sido relatada vantajosa para outras espécies, em condições hídricas desfavoráveis (4,5,14,19). Observações nesse sentido vêm sendo realizadas também com o cafeeiro.…”

“…A relação raiz/ parte aérea pode influir na tolerância à seca, como já foi constatado para diferentes espécies (4,5,14,19).…”