Identification of Associations between SSR Markers and Quantitative Traits of Maize (Zea mays L.)

Jan Bocianowski,Kamila Nowosad,Barbara Wróbel,Piotr Szulc

doi:10.3390/agronomy11010182

Abstract

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2).

Highlights

A total of 112 simple sequence repeat (SSR) markers were detected with the set of 30 SSR primers
The analysis of variance shows that the genotypes and years differed with regard to all the 26 traits of study
The genotype-by-year interaction was significant for all the observed quantitative traits

Summary

Introduction

Maize (Z. mays L.) belongs to the group of crops in which significant breeding progress has been observed in recent years. It is manifested by a large number of new hybrid varieties and by changes in the selection of different types of breeding [1]. All maize varieties offered for cultivation are hybrid varieties, characterized by exuberance, high vigor, and good alignment [2]. New maize varieties are characterized by better tolerance to a cold weather and a vigor of initial growth, as well as higher yield and lower moisture content during harvesting [4,5,6]

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