Exploiting wheat ancestral introgression for increased photosynthetic productivity under contrasting environmental conditions

Global population is expected to rise to 9 billion in another 40 years and changing climatic conditions coupled with various other abiotic and biotic stress factor have posed challenges for crop cultivars globally. Cereals like wheat, rice and maize have a central place in the human diet and require immediate attention in terms of improving yield in order to satiate the global food demand. This demand can be fulfilled by improving crop yield by exploiting natural variation in modern wheat by conventional breeding method like wheat ancestral introgression. One of the key traits that can be exploited such hybrids would be photosynthesis, ongoing debate and researcher have suggested that improving photosynthesis would be an attempt towards enhancing biomass and yield in crops like wheat and rice. In this project two different approaches were used to create interspecific hybrid, these hybrid were amphidiploids, which were created by chromosome doubling of haploid chromosome from wheat and wild relatives of wheat. First, a set of wild relatives were crossed bread wheat such as Highbury, Paragon, Chinese spring mutant, Chinese spring mutant and Pavon 76) and the amphidiploids created through these crosses where exploited for photosynthetic traits and other related physiological traits under glasshouse conditions. Second, amphidiploids created by cross using a wild relative Thinopyrum bessarabicum with durum wheat and tested in field conditions in India. Techniques like infra-red gas exchange, chlorophyll were used to assess photosynthetic performance in the glasshouse in optimal conditions and in the field under challenging environmental conditions. Along with the amphidiploids in the field conditions, a panel of 30 Indian genotypes were tested for natural variation in photosynthesis in field conditions. Almost similar set Indian genotypes were tested in glasshouse conditions in UK, to exploit the natural variation in photosynthesis. Initially, these Indian genotypes and amphidiploids grown in glasshouse as well as field conditions were screened for variation in photosynthesis. Promising lines derived from these instantaneous measurements were investigated for detailed photosynthetic measurements to understand the underlying biochemical mechanism that regulates photosynthesis and also were investigated leaf morphological and anatomical features for increased photosynthetic capacity. Here we show natural variation in photosynthesis in the amphidiploid population in both field and glasshouse conditions and range parameters that regulates photosynthetic rate in introgressed lines

Suboptimal acclimation of photosynthesis to light in wheat canopies

Photosynthetic acclimation (photoacclimation) is the process whereby leaves alter their morphology and/or biochemistry to optimise photosynthetic efficiency and productivity according to long-term changes in the light environment. Three-dimensional (3D) architecture of plant canopies impose complex light dynamics, but the drivers for photoacclimation in such fluctuating environments are poorly understood. A technique for high-resolution 3D reconstruction was combined with ray tracing to simulate a daily time course of radiation profiles for architecturally contrasting field- grown wheat canopies. An empirical model of photoacclimation was adapted to predict the optimal distribution of photosynthesis according to the fluctuating light patterns throughout the canopies. Whilst the photoacclimation model output showed good correlation with field-measured gas exchange data at the top of the canopy, it predicted a lower optimal light saturated rate of photosynthesis (Pmax) at the base. Leaf Rubisco and protein content were consistent with the measured Pmax. We conclude that although the photosynthetic capacity of leaves is high enough to exploit brief periods of high light within the canopy (particularly towards the base), the frequency and duration of such sunflecks are too small to make acclimation a viable strategy in terms of carbon gain. This suboptimal acclimation renders a large portion of residual photosynthetic capacity unused, and reduces photosynthetic nitrogen use efficiency (PNUE) at thecanopy level with further implications for photosynthetic productivity. It is argued that(a) this represents an untapped source of photosynthetic potential and (b) canopy nitrogen could be lowered with no detriment to carbon gain or grain protein content

Exploiting wheat ancestral introgression for increased photosynthetic productivity under contrasting environmental conditions

Global population is expected to rise to 9 billion in another 40 years and changing climatic conditions coupled with various other abiotic and biotic stress factor have posed challenges for crop cultivars globally. Cereals like wheat, rice and maize have a central place in the human diet and require immediate attention in terms of improving yield in order to satiate the global food demand. This demand can be fulfilled by improving crop yield by exploiting natural variation in modern wheat by conventional breeding method like wheat ancestral introgression. One of the key traits that can be exploited such hybrids would be photosynthesis, ongoing debate and researcher have suggested that improving photosynthesis would be an attempt towards enhancing biomass and yield in crops like wheat and rice. In this project two different approaches were used to create interspecific hybrid, these hybrid were amphidiploids, which were created by chromosome doubling of haploid chromosome from wheat and wild relatives of wheat. First, a set of wild relatives were crossed bread wheat such as Highbury, Paragon, Chinese spring mutant, Chinese spring mutant and Pavon 76) and the amphidiploids created through these crosses where exploited for photosynthetic traits and other related physiological traits under glasshouse conditions. Second, amphidiploids created by cross using a wild relative Thinopyrum bessarabicum with durum wheat and tested in field conditions in India. Techniques like infra-red gas exchange, chlorophyll were used to assess photosynthetic performance in the glasshouse in optimal conditions and in the field under challenging environmental conditions. Along with the amphidiploids in the field conditions, a panel of 30 Indian genotypes were tested for natural variation in photosynthesis in field conditions. Almost similar set Indian genotypes were tested in glasshouse conditions in UK, to exploit the natural variation in photosynthesis. Initially, these Indian genotypes and amphidiploids grown in glasshouse as well as field conditions were screened for variation in photosynthesis. Promising lines derived from these instantaneous measurements were investigated for detailed photosynthetic measurements to understand the underlying biochemical mechanism that regulates photosynthesis and also were investigated leaf morphological and anatomical features for increased photosynthetic capacity. Here we show natural variation in photosynthesis in the amphidiploid population in both field and glasshouse conditions and range parameters that regulates photosynthetic rate in introgressed lines