Genetic Mechanisms of Vernalization Requirement Duration in Winter Wheat Cultivars

Abstract

Wheat is cultivated across more land area than any other grain crops. Wheat cultivars are classifi ed as two general types: winter wheat with variable low temperature requirement for a proper fl owering time (vernalization) and spring wheat without the requirement, based on their qualitative vernalization requirement. Winter wheat cultivars are classifi ed as three types, weak winter, semi-winter and strong winter, according to their quantitative vernalization requirement to reach a vernalization saturation point or achieve the maximum vernalization effect. Three vernalization genes, VRN1 , VRN2 , and VRN3 , were cloned using a positional cloning approach and a one-gene model of qualitative variation in vernalization requirement between spring and winter wheat. A major gene for the vernalization requirement duration in winter wheat was mapped using a population of recombinant inbred lines (RILs) that were generated from two winter wheat cultivars, 'Jagger' and '2174'. Furthermore, the cloning population was developed using a RIL to backcross with 2174, which was segregated in a 3:1 ratio of the early fl owered plants and the late fl owered plants after the population was vernalized for 3 weeks. The wild type Jagger vrn-A1a allele for less vernalization was dominant over the 2174 vrn-A1b allele for more vernalization, and the two alleles encoded the vrn-A1 proteins with two point mutations. A third haplotype with one of the point mutations was found in common wheat. Gene markers were developed to direct breeding of semi-winter and strong winter wheat cultivars to adapt to different geographical areas and changing climates.

Estimating sowing and harvest dates based on the Asian summer monsoon

“…This is discussed by Sacks et al (2010) as a potential limitation when using the data for tropical and subtropical regions. Spring wheat is the more common type of wheat grown in the South Asia region (Hodson and White, 2007) because minimum temperatures there are not low enough to allow vernalization to take place, which is needed for winter varieties of wheat (Sacks et al, 2010;Yan et al, 2015). Figure 1 shows the averaged rice (green rectangles) and wheat (orange rectangles) growing season durations for Sacks et al (2010) (diagonal hatching) and the Bodh et al (2015) dataset (perpendicular hatching labelled MinAg) overlaid on the present day South Asia averaged precipitation climatology and estimates of the monsoon onset and retreat.…”

Origin and Distribution of the VRN-A1 Exon 4 and Exon 7 Haplotypes in Domesticated Wheat Species

“…Among the three homologous VRN1 genes, polymorphism in the coding sequence of the recessive allele (determining a winter growth habit), which is associated with the modulation of such agronomically valuable traits as the frost tolerance, vernalization requirement duration, days to stem elongation and flowering time of wheat, has been revealed only for the VRN-A1 gene [13][14][15][16].…”

Analysis of the VERNALIZATION-A1 exon-4 polymorphism in polyploid wheat

“…В настоящее время предложено несколько ДНК-марке-ров, идентифицирующих гаплотипы экзона-4 и 7 гена VRN-A1, большинство из них основаны на методе ре-стрикционного анализа фрагментов ПЦР (Chen et al, 2009;Eagles et al, 2011;Li et al, 2013;Yan et al, 2015). В неко- торых исследованиях гаплотип экзона-4 выявляли в ходе анализа хроматограмм секвенирования соответствующих ампликонов (Zhang et al, 2015) или субклонов (Chen et al, 2013), а также с использованием KASP-генотипирования (Díaz et al, 2012).…”

“…Доминантные аллели VRN1 обусловливают яровой или факультативный тип развития (отсутствие потребности в яровизации или ее частичное сохранение соответственно), тогда как рецессивные аллели характеризуются необхо-димостью в яровизации и обусловливают озимый тип развития. В то время как альтернативные доминантные аллели генов VRN1 оказывают различное влияние на ко-личественные показатели ряда качественных признаков в яровых сортах, полиморфизм рецессивного аллеля vrn1 ассоциирован с модуляцией чувствительности к про-должительности яровизации, морозостойкости, времени выхода в трубку и колошения озимой пшеницы (Chen et al, 2009;Dhillon et al, 2010;Eagles et al, 2011;Díaz et al, 2012;Li et al, 2013;Yan et al, 2015).…”