Screening techniques and sources of resistance to abiotic stresses in cool-season food legumes

Abstract

The adaptability and productivity of cool-season food legumes (chickpea, faba bean, lentil, pea) are limited by major abiotic stresses including drought, heat, frost, chilling, waterlogging, salinity and mineral toxicities. The severity of these stresses is unpredictable in field experiments, so field trials are increasingly supplemented with controlledenvironment testing and physiological screening. For drought testing, irrigation is used in dry fields and rain-out shelters in damp ones. Carbon isotope discrimination ( 13 C) is a well-established screen for drought tolerance in C3 cereal crops which is now being validated for use in grain legumes, but it is relatively expensive per sample and more economical methods include stomatal conductance and canopy temperature. Chickpea lines ICC4958 and FLIP87-59C and faba bean line ILB938 have demonstrated good drought tolerance parameters in different experiments. For frost tolerance, an efficient controlled-environment procedure involves exposing hardened pot-grown plants to subzero temperatures. Faba beans Cote d'Or and BPL4628 as well as lentil ILL5865 have demonstrated good freezing tolerance in such tests. Chilling-tolerance tests are more commonly conducted in the field and lentil line ILL1878 as well as derivatives of interspecific crosses between chickpea and its wild relatives have repeatedly shown good results. The timing of chilling is particularly important as temperatures which are not lethal to the plant can greatly disrupt fertilization of flowers. Salinity response can be determined using hydroponic methods with a sand or gravel substrate and rapid, efficient scoring is based on leaf symptoms. Many lines of chickpea, faba bean and lentil have shown good salinity tolerance in a single article but none has become a benchmark. Waterlogging tolerance can be evaluated using paired hydroponic systems, one oxygenated and the other de-oxygenated. The development of lysigenous cavities or aerenchyma in roots, common in warm-season legumes, is reported in pea and lentil but is not well established in chickpea or faba bean. Many stresses are associated with oxidative damage leading to changes in chlorophyll fluorescence, membrane stability and peroxidase levels. An additional factor relevant to the legumes is the response of the symbiotic nitrogen-fixing bacteria to the stress.

Legume Crops Phylogeny and Genetic Diversity for Science and Breeding

“…Significant genetic variation for all these traits of interest exists within faba bean germplasm, providing an excellent resource for plant breeders (Duc et al, 2010). Fast and reliable screening methods have been adjusted to fulfil the needs of breeding programmes both for fungal diseases , parasitic weeds and abiotic stresses (Stoddard et al, 2006). Many of these traits of interest have already been incorporated into modern cultivars but several others, many of which are controlled quantitatively by multiple genes, have been more difficult to manipulate.…”

Winter sowing of adapted lines as a potential yield increase strategy in lentil (Lens culinaris Medik.)

“…A cold tolerant Syrian landrace ('ILL4400', Stoddard et al, 2006), and eleven Spanish lentil cultivars, currently available to the Spanish farmers ('Águeda', 'Alcor', 'Aljama', 'Amaya', 'Ángela', 'Azagala', 'Candela', 'Guareña', 'Lyda', 'Magda' and 'Paula'), were included as checks.…”

Irrigation of Field Crops in the Boreal Region

“…Stoddard, personal communication). Furthermore, the European faba bean genotypes are more drought sensitive than genotypes from North Africa and Latin America (reviewed in Stoddard et al, 2006). The differences between genotypes in drought tolerance are marked.…”

“…According to McKenzie et al (1982), it seems that early maturing cultivars are more sensitive to frost than late maturing cultivars. Coolseason grain legumes are tolerant to frost at the vegetative stage, but pollen and flower structures are sensitive to low temperatures (Stoddard et al, 2006;Link et al, 2010;F. L. Stoddard, personal communication).…”

“…Pahkala et al (1991) reported a decrease in -linolenic acid and an increase in oleic acid concentration in ripening seeds of turnip rape after frost. Cool-season grain legumes are tolerant to frost at later stages of pod filling (Stoddard et al, 2006;Link et al, 2010;F. L. Stoddard, personal communication).…”