METHODS OF DAIKON BREEDING AND SEED PRODUCTION IN THE CRIMEA
At the first stage of breeding, the new source material was created to obtain a variety of daikon resistant to abiotic factors with high productivity and commercial qualities, better taste, and biochemical properties. Eighteen samples from Russia, Ukraine, Belarus, China, Korea, and Japan were in the nursery of the original forms. The following breeding types were used in the hybrid nursery: 1) crossing of several morphologically close samples originating from geographically remote areas; 2)
... remote areas; 2) paired crosses of morphologically and biologically different samples. Breeding was carried out on an accelerated scheme: before harvesting, samples were evaluated for resistance to bolting, shape and color of the roots, taste qualities, and affection with diseases; in February, the roots were planted in temporary greenhouses in pairs for hybridization; seeds were threshed in mid-July; the hybrid seeds were sown on the roots in early August; the roots were harvested and evaluated 60-65 days after the moment of sprouting. Then, the 1.5-year cycle was repeated until the constant lines were obtained. Yield fluctuations were determined by taking into account the sum of effective temperatures and precipitation for the period "sprouting – harvest" . Slight variability in the yield at high agronomic stability was observed for the varieties Sokol, Gulliver, and hybrid No. 41. The standard (variety Klyk slona) differed from other varieties by high variability in the yield and insufficiently high agronomic stability (66%). We found that there was the fluctuation of the yield of modern varieties: Klyk slona by 22 t/ha, Gulliver by 9 t/ha, Sokol by 14 t/ha, and hybrid No. 41 by 15 t/ha. It was estimated that for every 1 degree Celsius rise in the amounts of effective temperatures the yield of the aforementioned varieties decreased: 9.7; 38; 7.4 and 66 kg/ha, respectively. And, vice versa, if the amount of precipitation increased by 1 mm, the yield of Klyk slona would increase by 17 kg/ha, Gulliver - by 10 kg/ha, Sokol - by 11 kg/ha, and hybrid No. 41 – by 6 kg/ha. The technology and method for initial seed production of daikon have been developed with the preserved economic and biological characteristics. The daikon variety Sokol was created and included in the State Register.