The problem of soybean breeding on resistance to untimely dehiscence (shattering) of pods (report I)

The untimely dehiscence (shattering) of pods is an important factor in soybean yield losses that can reach 34-99 %. Cultivation of indehiscent genotypes in diverse environments often leads to loss of this resistance. This requires a more detailed and critical analysis used in the breeding methods and recommendations to reduce shattering of the pods. Anatomical and morphological study of the pods of dehiscent and indehiscent genotypes was carried out in 20122014 in VNIIMK, Krasnodar. Studies conducted on 25 plants of each of seven soybean accessions with the different resistance to shattering at the beginning and end of a seed ripening phase and after five and 30 days after pod maturation. Cross sections of pods investigated under a microscope at magnification of *40. It has been established that the soybean pod dehiscence always starts from the ventral suture, and only then goes to the dorsal side, causing a longitudinal gap of midrib. Previously described in the literature positive correlation between the size of the ventral sclerenchymatic bundles in the ventral suture and the conjunctive layer of parenchyma between them and the form of sclerenchymatic bundle in midrib on the one hand, and resistance to untimely dehiscence of pods - on the other hand, under the climatic conditions of the central zone of Krasnodar region is not confirmed by our research. Wide intravariety var iation of sizes and thicknesses of sclerenchymatic bundles in the ventral suture and midrib of pod is found. On the example of the study of dehiscent and indehiscent soybean varieties was shown that the basic anatomical and morphological traits of the soybean stability to shattering, described in the literature are not suitable for practical use in the breeding under climatic conditions of the Krasnodar region. This determines the necessity find additional traits in determining the untimely pods dehiscence sustainability.