Genetic variation in osmoregulation in bread and durum wheats and its relationship to grain yield in a range of field environments

Abstract

The association between osmoregulation and grain yield was examined using measurements of osmoregulation made on wheat plants grown in pots in a glasshouse and measurements of grain yields made in a wide range of field environments. Osmoregulation was determined from measurements of relative water contents and osmotic potentials made on the flag leaves of plants droughted near anthesis.The genotypes were advanced lines from two distinct breeding programsone for bread wheats and one for durum wheats. All the genotypes in each program (27 bread and 14 durum) were closely related in having a common parent. The grain yields of the bread wheats were evaluated in 56 field trials covering a period of 4 years, and those of the durum wheats were evaluated in seven field trials in one year. Both droughted and irrigated sites were represented. Four field environments were also included for F4 segregating lines reported previously. Considerable variation in osmoregulation occurred which was positively associated with grain yield over the full range of environments sampled for each genotype group. The yields of genotypes which were high in osmoregulation were 11-17% higher in bread wheats and 7% higher in durum wheats than those which were low in osmoregulation, when class differences were based on rnaximising the average yield differences between osmoregulation groups. These results add further evidence favouring the use of glasshouse measurements of osrnoregulation as a selection criterion in wheat breeding.

Assessing Drought Tolerance of Snap Bean (Phaseolus Vulgaris) From Genotypic Differences In Leaf Water Relations,Shoot Growth and Photosynthetic Parameters

“…4), which are important leaf anatomical characteristics for restricting leaf water loss through cuticle transpiration under drought conditions. Osmotic adjustment also enables the plants to maintain higher tissue water content, turgor and turgor-related processes during water deficit as reported in many crop species (Morgan et al, 1986;Ritchie et al, 1990;Kumar and Singh, 1998). In this study, there was a small decrease in osmotic potential, -1.0 to -0.87 MPa with a larger decrease in leaf water potential, -0.92 to -0.65 MPa (Table 1) indicating limited or no osmotic adjustment.…”

Genetics of osmotic adjustment in breeding maize for drought tolerance

“…Genetic variation for osmotic adjustment has been reported in wheat (Morgan, 1977(Morgan, , 1983Johnson et al, 1984;Morgan et a!., 1986), sorghum (Ackerson et a!., 1980;Shackel et al, 1982;Wright & Smith, 1983); millet (Henson, 1982;Henson et a!., 1982); rice (Turner et a!., 1986); cotton (Karami, et a!., 1980) and barley (Blum, 1989). However, little is known about the genetics of osmotic adjustment in tropical lowland maize.…”

Improving Drought-Avoidance Root Traits in Chickpea (Cicer arietinumL.) -Current Status of Research at ICRISAT

“…Although OA has been reported to be an important trait for drought tolerance in some cereal crops, e.g. wheat (Morgan et al, 1986) and sorghum (Tangpremsri et al, 1995), there are variable reports on the association of OA with grain yield in chickpea. Some studies have shown an association between OA and seed yield under water stress conditions (Morgan et al, 1991;Moinuddin and Khanna-Chopra, 2004), while some studies found inconsistent or no relationship (Singh et al, 1990;Leport et al, 1999).…”