Submitted to: Australian Journal of Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2009
Publication Date: 9/1/2009
Citation: Jaradat, A.A. 2009. Modeling Biomass Allocation and Grain Yield in Bread and Durum Wheat under Abiotic Stress. Australian Journal of Crop Science. 3(5):237-248.
Interpretive Summary: Abiotic stress caused by shorter growing seasons, competition for limited water resources or both are expected to impact wheat production. Dry matter production, partitioning into plant parts, and grain yield of bread and durum wheat were investigated under abiotic stress caused by shorter growing season and larger competition for resources during two years of contrasting growing conditions. Bread and durum wheat partitioned different ratios of accumulated dry matter into stems, leaves and seed in response to these stresses. Under abiotic stress, these ratios impacted several yield components and reduced grain yield by about 30-50%. Models were developed to quantitatively relate grain yield of bread and durum wheat to dry matter partitioning in response to abiotic stress. The information will assist wheat breeders and physiologists in identifying genetic resources of and deploying adaptive phenological and morphological traits to combat abiotic stress.
Technical Abstract: Dry matter (DM) partitioning into stems, leaves, and seed of two wheat (Triticum aestivum and T. durum) genotypes (A and D, respectively) in response to multiple abiotic stresses were quantified and their impact on kernel weight (KW, mg kernel**-1) and grain yield (GY, Mg ha**-1) was evaluated in a factorial experiment during two years of contrasting rainfall and temperature regimes. In addition to early (E) and late (L) planting, the population density was increased in each case by 25%, thus creating two extra stress levels (E+25, and L+25). Averaged over years, the stress levels, genotypes, and their interaction accounted for 68, 40, and 67% of variation in DM partitioned into stems, leaves, and seed, respectively; and for 75 and 37% of variation in KW and GY, respectively. DM partitioned into stems, leaves and seed was correlated (p<0.05) with KW (r= -0.35, -0.37 and 0.48, respectively), but not with GY, except for DM partitioned into leaves (r=-0.23, p<0.05). The AE and AE+25 partitioned the largest DM to leaves (16%), whereas DL+25 partitioned the least (7%). Largest and smallest DM partitioned into stems were those of AL (56%) and DL (28%), respectively, and largest and smallest DM partitioned into seed were those of AE+25 (54%) and AL (34%), respectively. The largest GY produced by AE+25 (4.59) and AE (3.98) was associated with intermediate KW (3.75 and 3.62, respectively); whereas the smallest GY produced by DL+25 (2.4) and DL (2.55) was associated with small KW (2.92 and 3.21, respectively). A stress-DM partitioning- GY or KW response model was developed for A and D, and can be used to develop selection indices for stress tolerance.