Dynamic Changes of Photosynthetic Characteristics in Xiaoyan 54, Jing 411, and the Stable Selected Superior Strains of Their Hybrid Progenies

Abstract

Xiaoyan 54, derived from the cross between Triticum aestivum L. and Thinopyrum ponticum, has special features of inherent higher cyclic photophosphorylation activity during photosynthesis and its higher tolerance to stresses. Many hybrid progenies of Xiaoyan 54 and Jing 411 were produced in the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, including several lines with stable characteristics. To explore their photosynthetic properties and provide theoretical basis or technical approaches for wheat breeding selection, the parents (Xiaoyan 54 and Jing 411) and the stable single-seed de- scent lines 6, 7, and 10 were planted in Shanghai in 2006–2008 growing seasons. Millisecond delayed light emission (ms-DLE) of their flag leaves at the heading stage was determined in 2007. The morpho-agronomic and yield traits of them were investigated in 2008. Net photosynthetic rate (Pn), chlorophyll content (Chl), specific leaf weight (SLW), Fv/Fm, ATP content, initial reduction rate of P700 in reciprocal first functional leaf of them during the different growth stages were determined for analyzing dynamic changes of photosynthetic characteristics in 2008. The morpho-agronomic traits of the lines 6 and 7 were similar to Xiaoyan 54 and Jing 411, respectively, and varied markedly in line 10. Photosynthetic characteristics of the parents and stable single-seed descent lines were closely related to the growth stages and measured indexes. Pn decreased in the order of tillering stage heading stage grain filling stage jointing stage; Chl content was different with grain filling stage ranking the first, followed by heading stage, tillering stage and jointing stage; ATP content was the order of grain filling stage jointing stage tillering stage heading stage; initial reduction rate of P700 was at grain filling stage heading stage jointing stage tillering stage; Fv/Fm at various growth stages were similar without significant differences. The heterobeltiosis of photosynthetic characteristics in wheat changed with different growth stages, such as the heterobeltiosis of Pn or Chl in line 10 was at grain-filling stage, heterobeltiosis of ATP content was at heading stage, SLW and initial reduction rate of P700 in each growth stage were the medium between the parents. Photosynthesis capacity was superior in line 10 than in the parents because of the heterobeltioses on Pn and contents of Chl and ATP. In lines 6 and 7, the photosynthesis capacity was inferior to and between the parents, respectively.