Influence of the different pod positions and screening methods on soybean pod shattering

Pod shattering is one of the major soybean constraints in the soybean production centers, particularly in the tropics. The screening for pod shattering resistance of 16 genotypes was carried out using detached and undetached pod methods on the three different pod positions on the stem. The field research was arranged in a randomized block design, during the dry season in Banyuwangi, Indonesia. The shattering evaluation was conducted in the laboratory using the ovendry method. The screening methods to investigate the pod shattering resistance of each genotype consisted of the detached pod (DP), undetached pod (UDP), and undetached whole-stem method (UWS). The result showed that the detached pod method (DP) resulted in a higher average podshattering percentage (15%) than the undetached pod methods (UDP and UWS, 13% and 11%, respectively). Nevertheless, the detached pod and undetached pod methods provide a consistent result for the evaluation of pod shattering resistance, showed by their correlation coefficients (DP and UDP, r = 0.98**; DP and UWS, r = 0.98**, UDP and UWS, r = 0.99**). The detached pod with the oven-dry method was suggested to be used for screening of pod shattering resistance. This method enables to screen genotypes in greater numbers, provides a homogeneous selection pressure and environmental condition. Pods at the upper part of the stem were more resistant to shattering than those pods in the middle part and lower part. The pod length, seed length, seed weight, pod wall weight to the pod weight ratio, and weight of 25 seeds appeared to be the significant indicators for pod shattering resistance. The shattering evaluation resulted in five soybean genotypes (Anj/G100H-28, Anj/G100H-44, Anj/Rjbs-304, Anj/Rjbs-30, and Detap 1) with consistent resistance to pod shattering based on the three methods. These genotypes can be used as donor parents in the breeding program for pod shattering resistance.

Identification and grouping of pod shattering resistance and agronomic characters performance from several soybean advanced lines

The use of pod-shatter resistant variety is considered effective in reducing yield loss in soybeans. This study aimed to identify and grouping of pod shattering resistance and agronomic characters performance from several advanced soybean lines. The field experiment was conducted in Blitar (Indonesia) from January to April 2021, using 20 soybean advanced lines and two check cultivars. The laboratory study to identify the pod shattering resistance based on the oven-dry method was conducted in the Breeding Laboratory of ILETRI, Malang. The pod shattering resistance of 20 advanced lines was classified into five very resistant genotypes, three resistant genotypes, two moderate genotypes, nine susceptible genotypes, and a very susceptible genotype. The pod shattering resistance has a significant negative correlation with the pod width (r = -0.472*). A wider pod resulted in a low percentage of shattering. The agronomic performance varied among all genotypes. Selection for pod shattering resistance and agronomic performance obtained two lines (G511H/Anjas//Anjas///Anjas-3-1 and Dega/Degra-2-105) as high yielding and very resistant to pod shattering. Those lines were suggested to be tested across diverse environments to determine their yield potential and stability.

Identification of Pod Shattering Resistance and Associations between Agronomic Characters in Soybean using Genotype by Trait Biplot

Background: Pod shattering has become the major problem in soybean production. The research aims to identify the pod shattering resistance and to assess the agronomic performances of 50 soybean genotypes and the association among agronomic characters. Methods: The research materials were 50 soybean genotypes which consisted of 47 lines derived from routine crossing programs and three check cultivars. The field experiment was arranged in a randomized block design with two replications. The data were observed for yield and its component traits. The oven-dry method was performed in the laboratory to assess the pod shattering resistance. Result: Variation among genotypes was found in the pod shattering resistance and agronomic characters. The genotype by trait biplot graph showed that pod shattering was negatively correlated with the days to maturity and plant height, but positively correlated with the seed size. Soybean genotypes of Grob/G100H-1-588 and G100H/Mhmr-4-993 were resistant to pod shattering and have a high seed weight per plant. These genotypes were potential for further varietal development or could be used as gene sources in the soybean improvement program for pod shattering resistance.

Shattering tolerance in Brassica napus L.

Brassica is the second-largest oilseed crop after Soybean. The total production of Brassica in the overall world is 71 million tons. In Pakistan, its total production per unit area is very low. Biotic and abiotic stresses mainly affect the brassica crop. In agriculture, shattering is the dispersal of crops seeds before their ripening. The pod wall shatters and breaks apart when it loses its hydration and cells split in a dehiscence zone organized at a suture between the edge of the lignified pod and the vascular tissue replum. The degeneration of middle lamella and loss of cellular cohesion in the dehiscence zone are the main reasons for pod shattering and seed losses. Grain yield losses in Brassica vary from 10 to 25 percent due to shattering. More than 400 kg has-1 or 12% seed losses can be occurred due to pod shattering under unfavorable conditions. Insect pest and disease damage also accelerate ripening and pod shattering. The main breeding techniques for developing rapeseed grain yield potential are a good knowledge and application of the morphological, physiological, and genetic basis of grain yield. Modern technologies, such as embryo rescue, marker-assisted breeding, and novel variation (mutation), may make it much simpler to introduce new rapeseed types having shattering tolerance than traditional methods. Thus, an overview of anatomical and physiological aspects and genetics of shattering is presented in the context of recent advances in molecular genetics and several agronomic managements to avoid shattering in Brassica.

Ascophyllum nodosum Extract (SealicitTM) Boosts Soybean Yield Through Reduction of Pod Shattering-Related Seed Loss and Enhanced Seed Production

Soybean is one of the most valuable commercial crops because of its high protein, carbohydrate, and oil content. The land area cultivated with soybean in subtropical regions, such as Brazil, is continuously expanding, in some instances at the expense of carbon storing natural habitats. Strategies to decrease yield/seed losses and increase production efficiency are urgently required to meet global demand for soybean in a sustainable manner. Here, we evaluated the effectiveness of an Ascophyllum nodosum extract (ANE), SealicitTM, in increasing yields of different soybean varieties, in two geographical regions (Canada and Brazil). In addition, we investigated the potential of SealicitTM to reduce pod shattering at the trials in Brazil. Three different concentrations of SealicitTM were applied to pod shatter-susceptible (SS) UFUS 6901 and shatter-resistant (SR) UFUS 7415 varieties to assess their impact on pod firmness. SS variety demonstrated a significant decrease in pod shattering, which coincided with deregulation of GmPDH1.1 and GmSHAT1–5 expression, genes that determine pod dehiscence, and higher seed weight per pod. SealicitTM application to the SR variety did not significantly alter its inherent pod shatter resistance, but provided higher increases in seed yield at harvest. This yield increase maybe associated with to other yield components stimulated by the biostimulant. This work demonstrates that SealicitTM, which has previously been shown to improve pod firmness in Arabidopsis and selected commercial oilseed rape varieties through IND gene down-regulation, also has the potential to improve pod resistance and seed productivity in soybean, a member of the legume family sharing a similar strategy for seed dispersal.

Pod Positions on the Plant Associated with Pod Shattering Resistance in Soybean Genotypes

Background: One of the major constraints of soybean production in Indonesia is pod shattering which occurs after soybean pod maturity. This study aimed to identify the pod shattering resistance of different pod positions in the plant stem. Methods: Sixteen genotypes were evaluated in the field research during the dry season 2019. The experiment was laid out in a randomized block design with three replicates. Ten sample plants were randomly taken after R8 phase. Plant was divided into three parts, i.e. upper part, middle part and lower part. The shattering evaluation was done using the oven-dry method in the laboratory. The observation on the number of shattered pods was measured for each part of plant stem. Result: Pod shattering was different among the pod positions as well as among genotypes. One genotype was categorized as resistant, eight genotypes were moderate, six genotypes were susceptible and one genotype was highly susceptible. The highest percentage of the shattered pods was in the lower part of the plant stem, followed by the middle and upper part, respectively. The resistant genotypes showed the shattered pods mostly in the lower part of the stem, the moderate genotypes showed the shattered pods mostly in the lower and middle part of the stem and the susceptible genotypes shattered in all part of the stem.