Table of contents: 2019
The morpho-agronomic characterization of gene banks is a key step in enabling breeding programs to efficiently exploit genetic resources. Several studies have evaluated the root system traits of the common bean to develop genotypes better adapted to drought. We examined the root systems of 1000 common bean accessions, from the Agronomic Institute of Campinas gene bank to: count the number of whorls and basal roots, estimate the divergence between accessions and evaluate the 47 most divergent genotypes under drought. The average numbers of whorl and basal roots for the 1,000 accessions were 2.07 and 8.09, respectively. Seven different clusters were identified using the Mahalanobis genetic divergence analysis and the Tocher optimization method, from which the 47 most divergent genotypes were selected. Both genotype and water treatments, in the pre-blooming period, significantly affected root length, root surface area, root volume, number of pods, seeds per plant and grain yield. However, only water treatment significantly affected stomatal conductance, with water treatment x genotype interaction only having a significant effect on this characteristic. Water deficit reduced the average grain yield by 52%; the most promising genotypes under water deficit considering both root growth and grain yield were: RAI 76, 56 Retinto Santa Rosa, SER 28, Bayo, IAC Una, IAC Bico de Ouro and 12-D.
Drought stress is a serious obstacle for crop production, especially in arid and semi-arid areas of the world. Sorghum is a useful crop to grow in areas with erratic, poorly distributed or inadequate rainfall. To help determine the best alternatives, we evaluated 30 sorghum cultivars with and without water stress in the post-flowering plant stage. The work was carried out at the Experimental Station of Gorutuba, in Nova Porteirinha, MG, Brazil, during 2013 and 2014 seasons. The experimental design was a randomized complete block, with three replications and two water regimes. The traits evaluated were grain yield, number of days to flowering, plant height and 1,000 grain mass. Water restriction reduced the grain yield by 68.9% in 2013, 31.2% in 2014 and 50.1% in the average of the two years. The genotypes with best grain yield stability were B.Tx635, SC 720 and BR012RxSC566. Water stress significantly reduced plant height and grain mass.