Growth Stress Response (Agronomical Stress Response)

Growth Stress Response Germination inhibition Growth reduction Premature senescence Reduction in productivity

Tolerance Yield base Use Efficiency base Yield: The reduction in yield under stress conditions compared to yield under optimal condition of cultivation Use Efficiency base The ratio between the yield and unit of resource available to the plant Yield: The combination of distinct independent processes (agronomical and Physiological component) Primary trait for selection in breeding programs aims at increasing yield potential and at achieving adaptation to stress –prone environment

Selection The way to improve genetic material Directly to a primary trait in a target environment (empirical breeding approach) Indirectly for a secondary trait that must be particularly putative to a higher yield potential and/or to employ behavior of crop when grown in a stressful environment (analytical breeding approach) Most of the progress has been derived from an empirical breeding by taken yield as the main trait for selection Traditional breeding reaches a plateau

Yield related traits Agronomic-traits A characteristics in plant that will add economic value to agricultural production Yield component Individual plant part directly contributing to yield on their number, size and/or weight Characteristics that contributed to economic yield The yield component of each crops are different, they should be evaluated through some statistical analysis To be useful in a breeding program, it must comply with several requirement:

Several General Requirements It must be genetically correlated with grain yield in the larger environment It should be less affected by environment that grain yield. It should have greater heritability than yield itself and less GE interaction It must show genetic variability within the species It should not associated with poor yield in unstressed environment It must lend itself to rapid and reliable measurement, and measurement should be less expensive than determining yield it self It must lend itself to assessment in individual plants or in vary small plot

Several Requirements to improve selection response to stress condition Improve precision Prevent confounding effect of stress on yield Focus the selection on specific type Cheaper, easier and faster to measure than grain yield

Difficulties in Abiotic Stress Breeding Screening techniques require high scale and are time consuming Creation of artificial condition is expensive Under field screening, it may not provide optimum conditions In vitro techniques are to be followed though it is expensive Abiotic stress breeding depends mostly on physiological traits which are not stable

It should base on yield response to stress condition Genotypes Grouping It should base on yield response to stress condition Group Category A Producing high yield under both stress and non stress condition B Producing high yield under non-stress condition C Producing high yield under stress condition D Producing low yield both under non-stress and stress condition