LINES-PRODUCERS OF HIGH SUGAR CONTENT IN ZEA MAYS L. SACCHARATA

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24.07.2015

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Abstract

Logistics of sweet corn hybrid breeding requires developing and using line material with high values of component sugars and total sugar content in breeding, which is an urgent task of our time.

Goal. To select producers of high sugar content and efficient sources of valuable for breeding traits among new lines – carriers of genes su1, sh2 and genetic combination su1se1 .

Results and Discussion. Alternative action of monogenic mutations su1, sh2 and combinations su1se1 provided minor differences in the monosaccharide formation (3.7-7.3%) for the groups of lines tested, while the disaccharide content ranged from 12.2% to 25.6% in su1 lines  and from 27.9% to 32.6% in sh2 genotypes. su1se1 lines occupied an intermediate position by this index between the first and second groups (25.0-32.0%). There was a broad diversification of the experimental groups of lines by peculiarities of the total sugar content. su1 lines synthesized from 15.9% to 32.8% of the total sugar. The highest sugar content (31.8-39.3%) was found in sh2 lines; in su1se1 accessions it was high enough (29.4-39.2%). The proportion of sucrose in the total sugar content was 50.6-59.3%, 63.0-71.7% and 59.0-65.3%, respectively, in the groups of lines.

Within the groups a significant divergence of line material by the parameters studied was noticed. Lines RKTs 18, RKTs 33, RKTs 38, RKTs 49, RKTs  80 of su1 type; ILS 3-2, ILS 19-1, ILS 2L6-2, ILS 27-2, PLS 7/5-1, PLS 10/5-1, PLS 64 5-1 of sh2 type; and RSE 12-1, RSE 13-1, RSE 14-1, RSE 17-1 of su1 combination with the monosaccharide content of 5.2-7.3%, disaccharide content of 22.9-32.6%, sucrose content of 16.2-24.7% and the total sugar content of 28.0-39.3% were the best. They are sources of high contents of different fractions of sugars. Lines RKTs 49, RKTs 80, ILS 27-2, PLS 64/5-1, RSE 13-1, RSE 17-1 RCE are recommended to use as references of these traits.

The results of analysis of morphological and biological traits of lines reflected diversity of material at the time of biological maturity of kernel. The highest productivity of plants were inherent to su1 lines, which gave on average of 69.6 grams of kernels per plant, while su1 and su1se1 genotypes gave 55.5 and 44.9 g, respectively. The maximum values of this trait in the best lines were 97.5 g, 69.8 g and 65.1 g or 186.8, 126.4 and 117.9%, respectively, related to the standard – line KS 209a. A high variability of the trait (V = 22.6%) suggested significantly heterogeneity of su1 lines unlike other groups, which were characterized by medium diversity of line material. Most of traits of ear productivity in all the groups were characterized by medium heterogeneity of line material, except the kernel number per row and 1000-kernel weight in su1 forms and kernel number per ear in su1se1 lines, determining their high genetic divergence.

The analysis selected lines - sources of individual economically useful traits as well as of their combination. Most of them are recommended to use as references upon expert evaluation of lines and systematization of line material.

Conclusions. It was found that new line material had a higher genetic background of sugar formation in comparison with lines of early breeding cycles. We distinguished efficient sources of high sugar content, individual traits of productivity and their constellation, which are formed in case of combination of high indexes of ear structure, peculiarities of carbohydrate biosynthesis in kernels and vegetative structure of plants in their genotypes. A trait collection comprising 33 lines with high sugar content and high indexes of morpho-biological traits was created. It represents the species diversity of sweet corn and meets requirements of practical breeding of corn hybrids adapted to cultivation under current conditions in different natural-ecological zones of Ukraine.

Keywords

Sweet corn, type of sugar biosynthesis, lines, traits, diversity, sources, references.