Seleção fenotípica em soja para estabilidade e tolerância ao excesso hídrico

Abstract

Soybean [Glycine max (L.) Merrill] is considered one of the most economically important crops. In Brazil, it is grown in considerable diversity of environments. Climate changes have influenced significantly agricultural production. This study aims to evaluate adaptability and stability of soybean genotypes and to select those tolerant to excess water in the shoot in mid northern state of Mato Grosso, Brazil as well to verify check its influence on yield and physiological quality of grains. So that, the study was divided into two chapters: in the first one, the experiment was carried out in Porto Alegre do Norte MT, in a randomized block design involving 25 genotypes and four commercial cultivars evaluated in three replications. Assays were performed in harvests of 2008/2009, 2009/2010 and 2010/2011. In order to evaluate adaptability and stability, we used the following methods: Eberhart & Russell (1966), Lin & Binns modified by Carneiro (1998), centroid (ROCHA et al., 2005) and Wricke (1965). In the second chapter, the experiment was carried out in Sygenta Seeds Research Center, in the city of Lucas do Rio Verde MT in a randomized block design in three replications with 15 treatments: 10 lineages of Sygenta soybean and six control ones (Pintado, MSOY8866, FTS4188, P98Y51, TMG131 e MSOY8888). We conducted a factorial design with seven harvest times (control group: five days first crop; 10 days second crop; 15 days third crop; 20 days - fourth crop; 25 days fifth crop and 30 days sixth crop after R8), one period of rain simulation (T1 - 3h of rain simulation) and three replications. We evaluated the performance of each genotype by measuring the following characteristics: number of days to flowering (NDF); number of days to maturity (NDM), plant height (cm) on flowering (PHF), plant height (cm) on maturity (PHM), height on the first pod (FPH), total weight (TW) and weight of 100 grains (GW). We used germination test to evaluate it. The vigor, viability, damage from moisture and mechanical damages were assessed by the tetrazolium test. We used Nuclear Magnetic Resonance (NMR) method to evaluate the protein and oil content. The results of the first chapter allowed us to verify that all methodologies agreed in detaching UFU-16 as the one with most productive performance and adaptability to favorable environment, but it showed low stability. By the method of Eberhart & Russel and Lin & Binns modified by Carneiro (1998) UFU-1 and UFU-14 lineages showed high average in grain productivity, high stability and were considered as adapted to favorable environment. However, both methods Lin Binns Lin Binns modified by Carneiro (1998 and Eberhart & Russel (1966) agreed on classifying the cultivars concerning to adaptability and stability. In the second chapter, we verified superiority in BRS Pintado cultivar concerning to total grain weight and the 100 grain weight. It was considered tolerant to excess water. Lineage 2 stands out to seed quality, with higher germination and vigor.