Evaluation of pollen fertility of sunflower hybrids by the method of split-pollination

The main objective of the study was to study the effect of pollen from sunflower hybrids on the real seed productivity and setting of achenes in CMS-tester plants as the final indicators of pollen fertility. The studies were carried out in 2019 and 2021 at V.S. Pusotvoit All-Russian Research Institute of Oil Crops, Krasnodar. The object of the study was cultivated sunflower plants of Helianthus annuus L.: Oksi and NK Brio hybrids as paternal forms, as well as the sterile hybrid Kubansky 93 and the line VK1-klp A as CMS testers. On one vertical part of a separate head, the pollen of the Oksi hybrid was applied, and on the other, the pollen of the NK Brio hybrid was used, i.e. we applied the split-pollination method. The number of fiiled seeds on the head of the CMS tester when pollinated with the pollen of the hybrid Oksi was significantly less than that of the standard hybrid NK Brio. On average, over two years, a decrease in real seed productivity was observed in the hybrid Oksi by 1.97 times in relation to the hybrid NK Brio. The development of a larger number of achenes to technical maturity led to the progressive growth of a part of the head pollinated by the pollen of the NK Brio hybrid. A similar pattern was also noted for the seed set. On the heads of the CMS-tester, on average for two years, the pollen of the hybrid Oksi showed a significant decrease in the setting of achenes in relation to the standard - by 2.24 times. Our earlier data on the presence of morphological anomalies in the pollen of the Oksi sunflower hybrid are consistent with the facts of reduced seed productivity and seed set when evaluating the pollen quality of this hybrid crossed with the CMS-tester, established in this work. The question remains open at what stages the negative impact of the genetic factors of the reproductive function of the pollen of the Oksi hybrid occurs: pre-or post-zygotic.