Effects of the 7DL.7Ag translocation from Lophopyrum elongatum on wheat yield and related morphophysiological traits under different environments

Abstract

The 7DL.7Ag translocation from Lophopyrum elongatum that carries Lr19, a leaf rust resistance gene, was found to be associated with a significant increase in grain yield under irrigated, disease-free conditions, but a generally lower yield under moisture stress conditions. These studies, however, involved a limited number of genetic recipients and environments, and the effect of the translocation on physiological traits was not considered. We examined the translocation effect in six different recipient genotypes and under five environmental conditions, including drought and heat stress. The increase in grain yield under irrigated conditions was associated with a higher rate of biomass production in the 7DL.7Ag lines and may be attributed to higher sink strength. Effect of the translocation on physiological traits was noted only under heat stress and was not associated with difference in yield. Under moisture stress conditions, 7DL.7Ag lines yielded less than their corresponding recipients, possibly because of a longer growing cycle. It is concluded that the effect of the 7DL.7Ag translocation may very much depend on the phenological adaptation of the recipient genotype and the translocation may be useful for enhancing yield, mainly under favourable conditions.

Molecular characterization of durum and common wheat recombinant lines carrying leaf rust resistance (Lr19) and yellow pigment (Y) genes from Lophopyrum ponticum

“…The development of isogenic lines for the distal 7EL segment in durum wheat lines UC1112 and UC1113 and for the proximal 7EL segment in hexaploid line 1-96, may provide valuable information for the location of the 7EL chromosome region associated with yield increases under irrigated conditions (Monneveux et al 2003;Singh et al 1998). …”

“…The original 7E chromosome was incorporated into cultivars 'Agatha' (Knott 1980), 'Oasis', and others (Monneveux et al 2003;Rajaram 2001). Agronomic characterization of several isogenic lines for this translocation demonstrated that the presence of the 7E Communicated by P. Langridge segment was associated with a yield increase under irrigated conditions (Monneveux et al 2003;Singh et al 1998).…”

“…Agronomic characterization of several isogenic lines for this translocation demonstrated that the presence of the 7E Communicated by P. Langridge segment was associated with a yield increase under irrigated conditions (Monneveux et al 2003;Singh et al 1998). In spite of its positive contribution to yield and leaf rust resistance, this segment has not been extensively used in agriculture.…”

The Potential of Lr19 and Bdv2 Translocations to Improve Yield and Disease Resistance in the High Rainfall Wheat Zones of Australia

“…One specific translocation on the 7DL chromosome of wheat, called variously 7Ag.7DL, Agatha or T4 [3][4][5], from Thinopyrum ponticum (tall wheatgrass), contained a number of characterized genes including Lr19 for leaf rust resistance, Sr25 for stem rust resistance, Sd1, a segregation distortion gene, and a linked gene deleterious for yellow pigment endosperm colour. This T4 translocation has also been associated with higher grain yield, anthesis biomass and delayed maturity in a number of genetic backgrounds [6][7][8]. Interestingly, the higher yield potential is only expressed under non-moisture stress conditions where yields exceed 2.5 tonnes per hectare [8].…”

“…This T4 translocation has also been associated with higher grain yield, anthesis biomass and delayed maturity in a number of genetic backgrounds [6][7][8]. Interestingly, the higher yield potential is only expressed under non-moisture stress conditions where yields exceed 2.5 tonnes per hectare [8].…”