<title>Abstract</title> This chapter describes the production environments; phenological adaptation to the environment; flowering response to photoperiod and temperature; and the impact of abiotic stresses (water availability, waterlogging, temperature, nutrient toxicity including salinity and sodicity, and mineral deficiency), diseases, and management (sowing time, weed control, and harvesting method) on adaptation of lentil. Improvement of adaptation through understanding genotype by environment interactions in lentil is discussed. To improve adaptation, the key traits that facilitate increased production (level and reliability of seed production), farming system benefit and price (quality of seed), or reduce cost must be identified, quantified and addressed through improved production technology and breeding. More specifically, profitability is a culmination of a species interaction with the environment, in particular the quantity and distribution of rainfall and temperature which influences the length of growing season, soil characteristics and biotic stresses, and cultural practices. Farming system benefits include those involved with rotation, such as providing a disease break or improving soil nutrition, weed management, and the timing and simplicity of total farm operation.
Quinolizidine alkaloids (QAs) are toxic secondary metabolites produced in lupin species that protect the plant against insects. They form in vegetative tissues and accumulate to a different extent in the grains: high levels in 'bitter' narrow-leafed lupin (NLL) and low levels in 'sweet' NLL. Grain QA levels vary considerably, and sometimes exceed the industry limit for food and feed purposes. We hypothesised that jasmonates regulate QA biosynthesis in response to environmental stresses such as wounding and aphid predation, which may explain non-genetic variability in grain QA levels. Methyl jasmonate (MeJA)-inducible genes were identified and verified in NLL. Exogenous MeJA application-induced expression of QA biosynthetic genes and QA levels for bitter, but not sweet NLL. Although MeJA-inducible genes responded to wounding, the expression of QA biosynthetic genes was not induced for bitter and sweet NLL. We assessed the effect of aphid predation on QA production for two cultivars - one moderately resistant and one susceptible to aphid predation. Although MeJA-inducible genes responded to aphid predation, no change in QA levels was found for either cultivar. These findings offer insights into the regulation of QA biosynthesis in bitter and sweet NLL and concludes that aphids are not a concern for increasing grain QAs in NLL cultivars.
Under rainfed Mediterranean-style conditions, crop growth and yield are largely determined by the availability of water. We investigated the role of residue orientation (standing or horizontal) and quantity on temperature, soil water, and wheat growth in two experiments with annual (winter) cropping. In the first trial at Shenton Park, tall (0.3 m) standing residues combined with thick (4 t ha−1) horizontal residues increased the soil water at sowing by more than 100 mm compared with the bare soil control, increasing the wheat yield by about 2 t ha−1. The average soil water storage was linearly related to the total residue quantity (r2 = 0.86). Both standing and horizontal residues reduced the daily soil temperature fluctuations, but increased the air temperature fluctuations. Tall-cut residues had higher maximum and lower minimum air temperatures 0.05 m above the ground than short-cut residues with more horizontal material. Under field conditions, more soil water was stored in the growing season with the residues cut relatively tall with less on the ground compared with an equivalent residue amount consisting of shorter residues with more on the ground, although the differences were not great. Tall stubble was also associated with greater green leaf area and PAR interception. At the Cunderdin trial, the residue was greater between the harvester wheel tracks than at the outer edge of the cutting front. Under the very dry seasonal conditions experienced during the trial, greater residue resulted in increased soil water storage, particularly in the top 0.5 m of soil (up to 29 mm), greater green leaf area index, and higher crop yields (up to 300 kg ha−1) behind the harvester, associated with greater spike m−2, greater spikelets spike−1, and lower root:shoot ratio. These results demonstrate the importance of considering residue orientation to maximise crop water use efficiency and yield.
