Morpho-biological traits and productivity of lines and hybrids of super sweet corn obtained on the basis of sh2 mutation

Abstract

Purpose. Super sweet corn contains a gene that, being expressed leads to an increase in the concentration of sugar. Endosperm genes that regulate the increase in sugar content and decrease in starch content were identified; the most effective of them were shrunken2 (sh2), brittle1 (bt), sugary1 (su1) and sugary enhancer1 (se). The recessive mutation of shrunken2 (sh2) provides a high content of sugars in the grain of milk-wax ripeness compared to other mutant forms that directly affects the taste of sh2-hybrids causes widespread use of this mutation in breeding and has the greatest commercial potential. The main task of breeding is to create a new generation of high-yielding hybrids; it depends on the availability of high-quality source breeding material. Therefore, the aim of our work was the assessment of morpho-biological traits of the super sweet corn lines, selection of the best donor lines of genetic traits, creating of high-yielding corn hybrids.Methods. Morpho-biological traits of the studied lines were evaluated according to the Classifier – handbook of Zea mays L. Comprehensive analysis of samples on economically valuable traits was carried out in accordance with the Methodical recommendations for field and laboratory study of genetic resources of corn. The content of reducing sugars in the grain of the studied corn lines and hybrids was determined by Bertrand method.Results. A study of morpho-biological traits of super sweet corn was carried out. Significant differences between the studied lines were observed in the vegetation period duration, the number of grains in one row and the number of grain rows in the cob. The lines-sources of economically valuable features that can be used for practical selection were identified. Crossing was carried out and 50 hybrid combinations were obtained; among them 16 hybrids cha­racterized by the best levels of economic characteristics were selected.Conclusions. As a result of the analysis of the main morpho-biological traits in hybrid combinations of super sweet corn with the mutant sh2 gene, the sources of selection-valuable traits were identified. According to the vegetation period, all lines were divided into three groups: early – 8 lines, middle – 6 and late – 8 ones. It was determined that promising donors of cob productivity were SH-621, SH-234 and SH-936 lines; signs of plant height – SH-234 and SH-936, number of grain rows – SH-234 and SH-113, cob lengths – SH-318 and SH-936. According to the results of studies of morpho-biological traits, the best lines were identified. They were crossed with other lines of super sweet corn and hybrids were obtained. The three best of them, ‘Matir Drakoniv F1’, ‘Yurmala F1’ and ‘Larus F1’, were submitted for state registration.