Allelic variation in major genes (Rht-B1, Ppd-A1 and Vrn-A1) and its effect on plant height, peduncle length and flowering/heading date in a durum wheat collection under field conditions

RONCALLO PABLO F.; LARSEN ADELINA OLGA; ZAFFORA BRUNO; MONTICELLI NICOLAS; DÍAZ GODOY PAOLO; ROCHÓN MARINA; CUESTAS JUAN M.; GONZÁLEZ LISARDO; JENSEN CARLOS; CAMPOS PABLO; MIRANDA RUBEN; DREISIGACKER SUSANNE; ECHENIQUE VIVIANA C.

Milan-Bologna

Conferencia; From Seed to Pasta & Beyond: A sustainable durum wheat chain for food security and healthy lives; 2015

Univ. of Bologna,CIMMYT,ICARDA, CRA, U. of Saskatchewan, etc.

Heading date is an important trait in wheat breeding as it affects adaptation and yield potential. Selection for height and the introduction of semi-dwarfing alleles at the Rht loci have been proven to be effective for wheat yield improvement. The aim of this work was to analyze the allelic variation in three major genes (Rht-B1, Ppd-A1 and Vrn-A1) in a durum wheat collection (Triticum turgidum L. var durum) and its phenotypic effects. Field trials were conducted during 2011 (133 entries, 2 environments), 2013 (168 entries, 2 environments) and 2014 (168 entries, 5 environments) using an alpha-lattice statistical design, in 5 assays. The genotyping was performed using the KASPTM genotyping technology and four single nucleotide polymorphisms (SNP) were detected in the 168 durum wheat genotypes. The effect of the allelic variation in these loci on the phenotype was assessed by using the ANOVA test, considering different number of field evaluations for each trait: peduncle length (4), plant height (5), spikes/m2 (5) heading date (8) and flowering time (1). The semi-dwarfing allele (Rht-B1b) was carried by 85.5% of the analyzed materials, showing a significant effect in all the environments with an average reduction in plant height (-23.6%) and peduncle length (-33.3%), but not showing a significant effect on the number of spikes/m2. Regarding to the heading date/flowering time traits, a relative high frequency of the spring allele Vrn-A1b (11.3%) at the Vrn-A1 locus (Marquis allele) and three alleles at the photoperiod A1 locus (Ppd-A1) (the deleted types `GS-100´, `GS-105´ and the intact allele) were detected. The combination of Vrn-A1b/intact sequence alleles (11.3%) for the haplotype Vrn-A1/Ppd-A1 showed, in average, a delay of 9.5 days in heading date respect to the genotypes carrying the `GS-100´ photoperiod insensitive allele. These are interesting results to be used for MAS in national durum breeding programs.