Peculiarities of winter rape pollen formation in the Eastern Forest-Steppe of Ukraine

Abstract

Plants of "00" varieties were found to produce by 26% more pollen than "0" varieties. 10% of "00" varieties and 80% of "0" varieties were the least particular about germination conditions judging by the pollen amount per flower. Conditions of the year had the greatest impact on the pollen grain size. The share of environment influence on the pollen grain size was 85.6% and 58.9% in "00" and "0" varieties, respectively. It revealed that the pollen grain shape changed depending on weather conditions: it was round under dry conditions and elongated ellipsoid under affluence or excess of moisture.

The aim and tasks of the study. Investigation of the pollen-forming ability of winter rape plants of "00" and "0" varieties and of the environment impact on the pollen formation in the Eastern Forest-Steppe of Ukraine.

Materials and methods. The investigation was conducted in the laboratory and in the field of the Plant Production Institute nd. a VYa Yuryev in 2012-2015. Twenty winter rape varieties of "00" and "0" types were evaluated for the pollen size, pollen amounts per flower and per the whole plant as well as for the pollen weight per flower and per the whole plant. The method of determining optical density of suspended pollen was used. Adaptability of varieties was calculated as SA Eberhart and WA Rassel described. Program STATISTIKA 10 was used to process data statistically.

Results and discussion. Our data showed that conditions of the year had the greatest impact on the pollen size both in "00" and in "0" varieties; the share of this influence was 85.6% and 58.9%, respectively. It was established that rape pollen was of round shape under dry conditions and the ratio of the smallest diameter of a pollen grain to the largest one was about 1, but under sufficient or excessive humidification pollen was of has elongated (ellipsoid) shape, and the ratio of the smallest diameter of a pollen grain to the largest one ranged from 0.75 to 0.91. We observed that varieties ‘Antariia’, ‘Galytskyy’, ‘Liradjet’, ‘Franki’, ‘Svitoch’ and ‘Yanus’ were the most plastic in terms of the pollen amount per flower, as the regression coefficient (b) was 0.96, 1.04, 0.96, 0.97, 1.00, and 1.02, respectively (within b = 1). The study of the pollen amount per flower showed that there were few "00" varieties adapted to cultivation on poor agricultural background or under unfavorable climatic conditions (b <1): 10% vs. 80% across "+0" varieties. Rape breeding maximally aimed at product quality is a probable cause of this phenomenon.

Conclusions. Specific effects of the factors "variety", "year", "year x variety" on parameters of pollen formation by winter rape varieties belonging to different types were detected.