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At the major vernalization locus ‘Vrn-D1’, the spring allele, Vrn-D1a, and two winter alleles, Vrn-D1b and vrn-D1, have been identified in wheat. We conducted field trials to determine the effects of alleles on growth and yield-related traits, using near-isogenic lines developed in the genetic background of spring type wheat cultivars, ‘Abukumawase’ and ‘Asakazekomugi’, both of which carry the Vrn-D1a allele. Although maturity date of three alleles was same, the panicle development occurred earlier in the following order of genotype: Vrn-D1a > Vrn-D1b > vrn-D1. There was a significant difference in panicle development even between two winter type alleles vrn-D1 and Vrn-D1b. Grain yield and the spikelet number per spike of the original spring type cultivars were lower than those of the winter type NILs. In addition, while the young panicle development of the tillers in the spring type cultivars was found to be two weeks to one month later in the tillers than that in the main stem, young panicle development of the main stem and tillers in the winter type NILs were almost identical. Hence, winter type wheat bearing vrn-D1 which exhibit later panicle development than that bearing Vrn-D1b, was elucidated to might be more useful especially in areas with high risk of frost damage. Spring type wheat had a lower sink capacity and grain yield, meanwhile that was considered to prevent severe frost damage by allowing late-developed tillers to survive.

At the major vernalization locus 'Vrn-D1', the spring allele, Vrn-D1a, and two winter alleles, Vrn-D1b and vrn-D1, have been identified in wheat. We conducted field trials to determine the effects of alleles on growth and yield-related traits, using near-isogenic lines developed in the genetic background of spring type wheat cultivars, 'Abukumawase' and 'Asakazekomugi', both of which carry the Vrn-D1a allele. Although maturity date of three alleles was same, the panicle development occurred earlier in the following order of genotype: Vrn-D1a > Vrn-D1b > vrn-D1. There was a significant difference in panicle development even between two winter type alleles vrn-D1 and Vrn-D1b. Grain yield and the spikelet number per spike of the original spring type cultivars were lower than those of the winter type NILs. In addition, while the young panicle development of the tillers in the spring type cultivars was found to be two weeks to one month later in the tillers than that in the main stem, young panicle development of the main stem and tillers in the winter type NILs were almost identical. Hence, winter type wheat bearing vrn-D1 which exhibit later panicle development than that bearing Vrn-D1b, was elucidated to might be more useful especially in areas with high risk of frost damage. Spring type wheat had a lower sink capacity and grain yield, meanwhile that was considered to prevent severe frost damage by allowing late-developed tillers to survive. [ABSTRACT FROM AUTHOR]

The duration of the vegetative period is an important agronomic characteristic of cereal crops. It is mainly influenced by the Vrn (response to vernalization) and Ppd (response to photoperiod) genes. In this work, we searched for alleles of several known genes of these two systems of response to external conditions in 15 accessions of Aegilops tauschii Coss. (syn. Ae. squarrosa L.), with the aim of studying the impact these alleles have on the vegetative period duration and growth habit. As a result, three allelic variants have been found for the Vrn-D1 gene: (i) one intact (winter type), (ii) one with a 5437 bp deletion in the first intron and (iii) one previously undescribed allele with a 3273 bp deletion in the first intron. It has been shown that the spring growth habit of Ae. tauschii can be developed due to the presence of a new allele of the Vrn-D1 gene. Significant differences in expression levels between the new allelic variant of the Vrn-D1 gene and the intact allele vrn-D1 were confirmed by qPCR. The new allele can be introgressed into common wheat to enhance the biodiversity of the spring growth habit and vegetative period duration of plants. [ABSTRACT FROM AUTHOR]

The duration of the vegetative period is an important agronomic characteristic of cereal crops. It is mainly influenced by the Vrn (response to vernalization) and Ppd (response to photoperiod) genes. In this work, we searched for alleles of several known genes of these two systems of response to external conditions in 15 accessions of Aegilops tauschii Coss. (syn. Ae. squarrosa L.), with the aim of studying the impact these alleles have on the vegetative period duration and growth habit. As a result, three allelic variants have been found for the Vrn-D1 gene: (i) one intact (winter type), (ii) one with a 5437 bp deletion in the first intron and (iii) one previously undescribed allele with a 3273 bp deletion in the first intron. It has been shown that the spring growth habit of Ae. tauschii can be developed due to the presence of a new allele of the Vrn-D1 gene. Significant differences in expression levels between the new allelic variant of the Vrn-D1 gene and the intact allele vrn-D1 were confirmed by qPCR. The new allele can be introgressed into common wheat to enhance the biodiversity of the spring growth habit and vegetative period duration of plants.

Molecular markers are developed to accelerate deployment of genes for desirable traits segregated in a bi-parental population of recombinant inbred lines (RILs) or doubled haplotype (DH) lines for mapping. However, it would be the most effective if such markers for multiple traits could be identified in an F2 population. In this study, single nucleotide polymorphisms (SNP) chips were used to identify major genes for heading date and awn in an F2 population without developing RILs or DH lines. The population was generated from a cross between a locally adapted spring wheat cultivar "Ningmaizi119" and a winter wheat cultivar "Tabasco" with a diverse genetic background. It was found that the dominant Vrn-D1 allele could make Ningmaizi119 flowered a few months earlier than Tabasco in the greenhouse and without vernalization. The observed effects of the allele were validated in F3 populations. It was also found that the dominant Ali-A1 allele for awnless trait in Tabasco or the recessive ali-A1 allele for awn trait in Ningmaizi119 was segregated in the F2 population. The allelic variation in the ALI-A1 gene relies not only on the DNA polymorphisms in the promoter but also on gene copy number, with one copy ali-A1 in Ningmaizi119 but two copies Ali-A1 in Tabasco based on RTPCR results. According to wheat genome sequences, cultivar "Mattis" has two copies Ali-A1 and cultivar "Spelta" has four copies Ali-A in a chromosome that was uncharacterized (ChrUN), in addition to one copy on chromosome 5A. This study rapidly characterized the effects of the dominant Vrn-D1 allele and identified the haplotype of Ali-A1 in gene copy number in the F2 segregation population of common wheat will accelerate their deployment in cycling lines in breeding. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) grain yield is predicted to decrease in the future because of an increase in air temperature globally. To clarify the effects of the vernalization response gene in wheat to warmer winters, we compared dry matter production and grain yield between spring wheat ‘Asakazekomugi’ and its winter-type near-isogenic line (NIL) carrying different alleles of the vernalization response gene Vrn-D1 under early-, standard-, and late-sowing conditions. Under early-sowing conditions, dry matter production of the NIL carrying the winter allele of Vrn-D1, named Asa (Vrn-D1b), exceeded that of ‘Asakazekomugi’ from mid-March (after stem elongation in Asa (Vrn-D1b)) when the temperatures rose. Tiller number and leaf area index under early-sowing conditions were consistently higher in Asa (Vrn-D1b) than in ‘Asakazekomugi’ from mid-March onward. It was suggested that the early-sown ‘Asakazekomugi’ could not effectively absorb solar radiation to produce dry matter because of the acceleration of stem elongation caused by the Vrn-D1 gene during the cold season. The grain yield of Asa (Vrn-D1b) with early sowing was higher than with standard sowing. In contrast, the grain yield of ‘Asakazekomugi’ was lower in the early-sown crop than in the crop sown at the standard date. These results suggested that the higher grain yield of Asa (Vrn-D1b) than that of ‘Asakazekomugi’ under early-sown conditions could be due to Asa (Vrn-D1b) maintaining high dry matter production after the jointing stage by suppressing acceleration of growth caused by warm conditions after sowing. Abbreviations CGR: crop growth rate; HI: harvest index; LAI: leaf area index; NIL: near-isogenic line; SNP: single-nucleotide polymorphism

Wheat (Triticum aestivum L.) grain yield is predicted to decrease in the future because of an increase in air temperature globally. To clarify the effects of the vernalization response gene in wheat to warmer winters, we compared dry matter production and grain yield between spring wheat 'Asakazekomugi' and its winter-type near-isogenic line (NIL) carrying different alleles of the vernalization response gene Vrn-D1 under early-, standard-, and late-sowing conditions. Under early-sowing conditions, dry matter production of the NIL carrying the winter allele of Vrn-D1, named Asa (Vrn-D1b), exceeded that of 'Asakazekomugi' from mid-March (after stem elongation in Asa (Vrn-D1b)) when the temperatures rose. Tiller number and leaf area index under early-sowing conditions were consistently higher in Asa (Vrn-D1b) than in 'Asakazekomugi' from mid-March onward. It was suggested that the early-sown 'Asakazekomugi' could not effectively absorb solar radiation to produce dry matter because of the acceleration of stem elongation caused by the Vrn-D1 gene during the cold season. The grain yield of Asa (Vrn-D1b) with early sowing was higher than with standard sowing. In contrast, the grain yield of 'Asakazekomugi' was lower in the early-sown crop than in the crop sown at the standard date. These results suggested that the higher grain yield of Asa (Vrn-D1b) than that of 'Asakazekomugi' under early-sown conditions could be due to Asa (Vrn-D1b) maintaining high dry matter production after the jointing stage by suppressing acceleration of growth caused by warm conditions after sowing. Abbreviations: CGR: crop growth rate; HI: harvest index; LAI: leaf area index; NIL: near-isogenic line; SNP: single-nucleotide polymorphism [ABSTRACT FROM AUTHOR]

Molecular markers are developed to accelerate deployment of genes for desirable traits segregated in a bi-parental population of recombinant inbred lines (RILs) or doubled haplotype (DH) lines for mapping. However, it would be the most effective if such markers for multiple traits could be identified in an F 2 population. In this study, single nucleotide polymorphisms (SNP) chips were used to identify major genes for heading date and awn in an F 2 population without developing RILs or DH lines. The population was generated from a cross between a locally adapted spring wheat cultivar "Ningmaizi119" and a winter wheat cultivar "Tabasco" with a diverse genetic background. It was found that the dominant Vrn-D1 allele could make Ningmaizi119 flowered a few months earlier than Tabasco in the greenhouse and without vernalization. The observed effects of the allele were validated in F 3 populations. It was also found that the dominant Ali-A1 allele for awnless trait in Tabasco or the recessive ali-A1 allele for awn trait in Ningmaizi119 was segregated in the F 2 population. The allelic variation in the ALI-A1 gene relies not only on the DNA polymorphisms in the promoter but also on gene copy number, with one copy ali-A1 in Ningmaizi119 but two copies Ali-A1 in Tabasco based on RT-PCR results. According to wheat genome sequences, cultivar "Mattis" has two copies Ali-A1 and cultivar "Spelta" has four copies Ali-A in a chromosome that was uncharacterized (ChrUN), in addition to one copy on chromosome 5A. This study rapidly characterized the effects of the dominant Vrn-D1 allele and identified the haplotype of Ali-A1 in gene copy number in the F 2 segregation population of common wheat will accelerate their deployment in cycling lines in breeding., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wu, Qiao, Liu, Fu, Nagarajan, Rauf, Jia and Yan.)