Peculiarities of pea breeding upon selections in primary nurseries

Abstract

Purpose and objective. The study purpose was to determine the effectiveness of the selection methods used in breeding by summarizing practical experience.

Material and methods. Initial material was grown in primary (hybrid, breeding) nurseries of the Laboratory of Pea Breeding (Laboratory of Grain Legume Breeding from on 01.2019) in 2007–2018.

Results and discussion. In the Laboratory of Grain Legume Breeding, selections in the hybrid pea nursery (F₁ plants, A × B crossing design) are aimed at the general assessment of a combination - plant development, evenness of hybrids, affection by diseases and pests. Diseased hybrid populations are completely eliminated. More careful selections are conducted in F₁ in combinations designed by (F₁ (A × B) × C), in which one of the parents (A or B) was leafy, and the others were leafless. In this case, when selecting for leaflessness, one leaves leafy hybrids for replanting and further selections, and leafless plants are sown in the breeding nursery. In the same way, from populations derived by a similar design, plants are selected for monogenic traits (shedding resistance - the df gene (funicularity); stem length - gene le, etc.).

During the study period (2007–2018), the percentage of plants selected from the hybrid nursery averaged 14.8% (2,424 plants), with the lowest figure in 2014 of 0.8%. It should be noted that such a small percentage of the selected plants in 2014 was due to extremely strong aphid-induced damage to pea plants and spread of viral diseases.

The plants selected in F₁ are threshed and sown in the breeding nursery, where individual selections are conducted, depending on the direction of breeding.

The main method of working with a pea hybrid population in the Laboratory is individual selection followed by evaluation of offspring - the pedigree method. Selections in F₂ are carefully carried out, with due account for individual productivity of each plant, its affection by diseases and pests. We evaluate the stem length, the number of vegetative nodes before the first productive one, the number of productive nodes and pods per node, paying attention not only to their total number and pairing, but also to the presence and plumpness of beans on the upper productive nodes. We also measure the seed number per pod. In F₃, offspring is assessed for evenness and the vegetation phase lengths. In F₄-₅, only even high-yielding families are selected; they are threshed; and the total number of seeds is estimated. General requirements for the selection of hybrid and breeding material depend only on the direction of breeding.

Conclusions. The application of the pedigree method in pea breeding is time-consuming for breeders and demands thoroughness at all stages. However, this approach allows detailed investigating hybrid material at the beginning of the breeding process, which increases the breeding effectiveness. The effectiveness of the applied methods and selection ways is confirmed by demand for pea varieties bred at the Plant Production Institute named after VYa Yuriev and positive feedback from manufacturers.