Selection of soybean lines exhibiting resistance to stink bug complex in distinct environments

Abstract

In soybean, stink bugs are considered the most important pest insect as they feed directly from the grain, causing significant losses in seed yield and quality. The use of resistant genotypes is a promising strategy to control these insects. Focusing on selection of soybean lines with resistance and high yield potential, 251 recombinant inbred lines (RILs), derived from a cross between IAC‐100 (resistant) and CD‐215 (susceptible), were evaluated in two experiments, designed as alpha‐lattice, with three replicates in Piracicaba, during the growing seasons of 2012/13 and 2013/14. The evaluated traits were as follows: number of days to maturity (NDM), plant height at maturity (PHM), grain filling period (GFP), lodging (L), agronomic value (AV), grain yield (GY), weight of a hundred seeds (WHS), leaf retention (LR), and healthy seeds weight (HSW). Variance components were estimated by the Restricted Maximum Likelihood method (REML). Heritability and selection gain (SG) parameters were also calculated. Selection was carried out based on 2012/13 season, considering the genotypes that exhibited a minimum HSW of 2908.26 kg ha−1 (acceptable losses of 20% from the average GY). Insect population was monitored by cloth beating. An increase in stink bug population was observed during the grain filling period, with the highest population density occurring in the season 2012/13. Estimates of the variance components demonstrated the elevate influence of the interaction genotype x environment on GY and HSW, which exhibited the lowest estimates of heritability (23 and 34%, respectively). The estimate selection gain, calculated from the predicted means of GY and HSW, was of 665.4 and 482.4 kg ha−1 season 2012/13. Therefore, the applied selection allowed the identification of the genotypes exhibiting higher yields and resistance to the stink bug complex. From the RIL population, lines or genotypes potentially useful to generate novel cultivars were identified.

Research Article Line selection and correlation between traits of soybean genotypes under high naturally occurring stink bug infestation

“…Rocha and collaborators (2014) emphasized the weight of a hundred seeds as a useful trait in simultaneous selection for high yield and resistance to the stink bug complex, as well as the importance of those types of resistance associations as a strategy to lower costs for farmers. Leite and collaborators (2016) found 0.57 (phenotypic) and 0.78 (genotypic) correlations between grain yield and total number of pods, which agrees with the results found in the current study and reinforces the importance of number of pods for achieving high yielding soybean genotypes (Alcantara Neto et al, 2011;Rocha et al, 2015;Leite et al, 2016).…”

“…The association between the number of days to maturity and both grain yield and weight of one hundred seeds were highly negatively correlated, -0.65 and -0.63, phenotypically, and -0.74 and -0.69, genotypically, respectively. Similar results were observed by Rocha et al (2015), as the longer plant cycles are, the exposure of the plant to the attack of pests increases. Table 6 Coefficient of phenotypic (r p ) and genotypic (r g ) correlations between fifteen traits from 27 soybean genotypes over the growing season of 2015/2016 in Uberlândia.…”

“…The number of days to bloom and maturity are important parameters as the longer time soybean genotypes need to complete their cycle, the more time of exposure to the attack of stink bugs there is (Rocha et al, 2015). Therefore, in a natural occurring infestation scenario early genotypes tend to escape from the attack of pests by a host evasion type of resistance, and consequently, maintain higher grain yield by shortening the most susceptible stages of the crop, R5 to R7 (Corrêa- Ferreira et al, 2013;Rocha et al, 2015;Fernandes et al, 2017).…”

“…They oscillated from 6.1 (UFUS MILIONÁRIA) to 12 g (G21) (Table 4), which shows the impact of stink bugs on reducing soybean seeds weight. A pseudo-resistance mechanism, defined as damage dilution type, may reduce the proportional number of damaged seeds due to insect attack by increasing the number of seeds per plant (Rocha et al, 2015).…”

“…Line selection and correlation between traits of soybean genot Rocha et al, 2015 tolerance the attack of stink bug complex, as well as have desirable phenotypic and genotypic correlations is very important for the success of soybean cult 2017).…”