The physiological genetic effects of 1BL/1RS translocated chromosome in stay green wheat cultivar CN17

Rye (Secale cereale L.) chromosome arm 1RS in the wheat (Triticum aestivum L.) genetic background has potential significance for yield improvement without affecting its resistance to several diseases. A new wheat cultivar, Chuannong17 (CN17), carrying the wheat-rye 1BL/1RS translocated chromosome, exhibited “stay green” phenotypes. To determine the genetic behavior and physiological effect, MY11, CN17, BC 1 F 1 , and F 2 populations of MY11/CN17 were grown in the normal wheat growing seasons in 2004–2005 and 2005–2006. Analysis of photosynthetic parameters showed that the coordinate increase of net photosynthetic rate (P n ), stomatal conductance (G s ) and flag leaf area duration from anthesis to maturation (D 2 ) would be the physiological basis of the high yield potential of the 1BL/1RS translocation (CN17). The analysis for morphological indices proposed that the smaller leaf length (L l ), flag leaf width (L w ) and angle between stem and flag leaf (A) would be responsible for the morphological basis of the high yield potential. Analysis of the relationship between the yield and physiological indices suggested that the coordinate increase of source, the partitioning of assimilate from source to sink, and the sink strength was the material basis of the high yield potential. These results afforded some persuasive evidence to support the idea that wheat cultivar CN17 also shows a coordinate relationship between physiology and morphology and is indeed functionally a “stay green” cultivar. The results show that exploitation of a foreign chromosome or chromosome arm such as 1RS to develop “stay green” genotype cultivars in wheat breeding has the potential to increase yields. Key words: 1BL/1RS translocated chromosome, photosynthesis, physiological genetic effect, stay green, wheat