Grain legume production is increasing worldwide due to their use directly as human food, feed for animals, and industrial demands. Further, grain legumes have the ability to enhance the levels of nitrogen and phosphorus in cropping systems. Considering the increasing needs for human consumption of plant products and the economic constraints of applying fertiliser on cereal crops, we envision a greater role for grain legumes in cropping systems, especially in regions where accessibility and affordability of fertiliser is an issue. However, for several reasons the role of grain legumes in cropping systems has often received less emphasis than cereals. In this review, we discuss four major issues in increasing grain legume productivity and their role in overall crop production: (i) increased symbiotic nitrogen fixation capacity, (ii) increased phosphorus recovery from the soil, (iii) overcoming grain legume yield limitations, and (iv) cropping systems to take advantage of the multi-dimensional benefits of grain legumes.

Chromosomal substitution lines of wheat variety Timstein (Tim) into the genetic background of variety Chinese Spring (CS) were used to evaluate the chromosomal location of genes controlling carbon isotope discrimination (Δ), photosynthesis rate (PR), stomatal conductance (SC), and grain yield. The experiment was carried out in the field at Shahrekord University Research Station. Considerable variation was observed among the substitution lines and between the parents for all traits. Chinese Spring had smaller values for the characters under study than Timstein. Significant correlations were found for grain yield with PR (r = 0.556) and Δ (r = 0.619). The substitution line CS (Tim2B) was significantly different from CS for Δ (P < 0.01). The substitution of homeologous group 3 chromosomes produced significant differences from the recipient variety for PR. Substitution lines CS (Tim3A), CS (Tim3B), CS (Tim4B), and CS (Tim1D) were significantly different from CS for SC. Genomic comparisons indicated that genome B had higher values of all four characters compared with the A and D genomes. Homeologous effects of genomes were documented for Δ and PR only and not for SC and grain yield.

Conventional rainfed mixed crop–livestock systems of western China lack high-quality forage and restrict livestock production. This study explored the forage potential from wheat and its effects on subsequent grain yield. Different cutting times were imposed on winter wheat (Triticum aestivum) at Qingyang, Gansu Province, in two growing seasons, and the effect of nitrogen (N) topdressing rates (0, 60, and 120 kg N/ha) on grain yield recovery was explored. Results showed the potential to produce 0.8–1.6 t DM/ha of wheat forage with high nutritive value when cut before stem elongation (GS 30). In the wetter year, cutting before stem elongation did not delay crop development significantly (<3 days at anthesis and 5 days at maturity), but grain yields were reduced by 17–28% compared with the uncut crop (5.8 t DM/ha), mainly due to reductions in number of spikes per m² and, consequently, number of grains per m². In both seasons, more forage biomass was available if crops were cut later than GS 32, but this came with large reductions (>62%) in grain yield and delays in crop development (>9 days or 131 degree-days). Crops cut later than GS 30 had greatly reduced harvest index, tillers per m², and total N uptake but higher grain protein content. There was no significant effect of N topdressing rate on grain yield, although provided the crop was cut before GS 30, higher rates of N increased maturity biomass and crop N uptake by replacing N removed in cut biomass. This study showed that physiological delay of wheat due to cutting was not significant. The forage harvested from winter wheat before stem elongation could be a valuable feed resource to fill the feed gap in western China.

Drought is a major limiting factor for the production of rainfed rice in the Mekong Region. Thus, estimation of the length of growing period (LGP) based on estimation of the development of water deficit is essential for sound planning of agricultural development. A recently developed soil-water balance model was used to quantify the availability of water for rice crops and yield reduction due to water deficit. Field water availability is known to be largely affected by soil type and rainfall pattern, and their separate effects were investigated in this study of a spatial analysis of LGP, using inputs for rainfed lowland rice in Savannakhet province in central Laos. The analysis showed that the start of growing period (SGP) and end of growing period (EGP) were affected largely by geographical variations in rainfall and soil clay content, respectively. Also, the areas having relatively short LGP were generally associated with large yield reduction because of low water availability associated with coarse-textured soils. At local scale, field water availability varied from upper to lower positions of a sloping land (toposequence) in the rainfed lowland ecosystem of the Mekong region, causing variation in yield within the toposequence. Using the level of field water determined around flowering time at different toposequence positions in 45 farms, estimated yield reduction was compared in seven main rice-growing districts of the province. Variability of yield loss, associated with variation in water availability, was larger across the toposequence positions than across districts, showing the importance of local variability in determining yield in rainfed lowland rice. The present approach of a combination of simulation model and GIS is adopted for characterisation of the water environment for rainfed lowland rice in other parts of Laos, as well as in neighbouring Thailand and Cambodia.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a fungal disease that causes significant yield losses in many wheat-growing regions of the world. Previously, five quantitative trait loci (QTLs) for adult-plant resistance (APR) to stripe rust resistance were identified in Italian wheat cultivar Libellula. The objectives of this study were to map QTLs for APR to powdery mildew in 244 F_2 : 3 lines of Libellula/Huixianhong, to analyse the stability of detected QTLs across environments, and to assess the association of these QTLs with stripe rust resistance. Powdery mildew response was evaluated for 2 years in Beijing and for 1 year in Anyang. The correlation between averaged maximum disease severity (MDS) and averaged area under disease progress curve (AUDPC) over 2 years in Beijing was 0.98, and heritabilities of MDS and AUDPC were 0.65 and 0.81, respectively, based on the mean values averaged across environments. SSR markers were used to screen the parents and mapping population. Five QTLs were identified by inclusive composite interval mapping, designated as QPm.caas-2DS, QPm.caas-4BL.1, QPm.caas-6BL.1, QPm.caas-6BL.2, and QPm.caas-7DS. Three QTLs (QPm.caas-2DS and QPm.caas-6BL.1, and QPm.caas-6BL.2) seem to be new resistance loci for powdery mildew. QTLs QPm.caas-2DS and QPm.caas-4BL.1 were identified at the same position as previously mapped QTLs for stripe rust resistance in Libellula. The QTL QPm.caas-7DS, derived from Libellula, coincided with the slow rusting and slow mildewing locus Lr34/Yr18/Pm38. These results and the identified markers could be useful for wheat breeders aiming for durable resistance to both powdery mildew and stripe rust.

Lentil is one of most important pulse crops in South Asia, and invariably encounters terminal moisture stress, leading to forced maturity and lower yield. A long and prolific root system is known to enhance capacity of the plant to extract water from the lower soil strata and thus help avoid the water stress. We assessed genetic variation for 12 traits among 43 lentil genotypes comprising improved varieties and promising breeding lines. The average root length at the 65-day plant stage ranged from 42 to 83 cm. Two genotypes (EC 208362 and VKS 16/11) with shorter root length and poor dry root weight (DRW) and three genotypes (DPL 53, JL 1, and IPL 98/193) with longer root length and high DRW were identified with stable performance over the years. Relationship of root traits with seed yield under rainfed conditions was non-significant in our study. The SPAD value (chlorophyll content) showed significantly positive correlation with DRW (r = 0.45**) and root length (r = 0.44**) and thus can be used as selection criterion for phenotyping root traits which are otherwise difficult to measure in the field. In drought-prone environments, early flowering and maturity, seedling vigour, and high SPAD value, biological yield, and harvest index were identified as key traits for higher seed yield in lentil. Our results revealed significant genetic variability for these traits in lentil germplasm. Indian genotypes adapted to rainfed conditions were shown to have longer roots and higher DRW. The three genotypes (DPL 53, JL 1, and IPL 98/193) identified with superior root traits either originated from or have in their ancestries at least one parent adapted to rainfed conditions. These genotypes can be utilised for the development of mapping populations to identify QTLs associated with these traits for marker-assisted breeding of drought-tolerant, high-yielding varieties of lentil.

Mallee-based agroforestry has potential to provide farmers with new income sources derived from biofuels, biofeedstocks, and carbon sequestration. Although mallees are planted on >12 700 ha across the south-west of Western Australia, very little commercial harvesting of mallee has occurred to date. The development of biomass processing industries is constrained by lack of robust information regarding the productivity of integrated mallee and agricultural systems. This study addresses this constraint by quantifying the productivity and economics of agricultural crops and pastures growing in the competition zone adjacent to mallee belts at 15 sites across the Western Australian wheatbelt. The sites covered a range of climate and edaphic conditions, three mallee species (Eucalyptus polybractea R Baker, E. loxophleba ssp. lissophloia LAS Johnson and KD Hill, or E. kochii ssp. plenissima (CA Gardner) Brooker), various crop and pasture rotations, and various mallee harvest-management treatments.

Mallee–crop competition was negatively correlated with rainfall and positively correlated with mallee age and size, and greater for crops than pasture. Consequently, extent and magnitude of competition were highly variable across sites and years. On average, mallee–crop competition extended 11.3 m from unharvested belts and reduced crop and pasture yields by 36% within 2–20 m of the mallee belts relative to open paddock yields. This is similar to what has been reported for taller tree species. Harvesting mallees reduced competition such that crop and pasture yield was reduced by 22 or 27% relative to open paddock yields for mallees harvested at 3- or 6 -year intervals, respectively.

The economic cost of mallee–crop competition on agricultural enterprises was also highly variable between sites, and between years within individual sites. Averaged across all site-years, the opportunity cost of competition was equivalent to forgoing agricultural production for 14.4 m on each side of unharvested mallee belts, or 9–10 m on each side of harvested belts.

Farmers with mallee agroforestry systems will need to manage the economic impacts of competition by reducing agricultural input costs in the competition zone, timing crop-grazing rotations with mallee harvests, ensuring that the width of alleys is at least 25 times the height of the mature trees, and possibly root-pruning mallees in unharvested or long harvest interval systems.

This research has shown that mallee–crop competition presents a significant cost to farmers and must be considered when designing mallee agroforestry systems. The findings have relevance for the development of appropriate biomass and carbon sequestration pricing benchmarks for mallee plantings.

Amphicarpy, an adaptive trait whereby both aerial and underground fruits are formed on the one plant, occurs in several plant taxa, notably the Phaseoleae legumes. Amphicarpic species offer the dual potential benefits of enhanced persistence through their underground seed, combined with ease of harvest of their aerial seed. While amphicarpy has been reported in several endemic Australian tropical legumes, information on the trait is sparse. The objective of the current research was to compare aerial and underground reproductive structures in amphicarpic tropical legumes from four different sub-tribes within the Phaseoleae: three Australian endemic species, Vigna lanceolata (sub-tribe Phaseolinae), Flemingia pauciflora (sub-tribe Cajaninae), and Glycine falcata (sub-tribe Glycininae); and the exotic pasture legume Centrosema rotundifolium (sub-tribe Clitoriinae). As far as we know, this report of amphicarpy in F. pauciflora is the first record of the trait in a member of the Cajaninae. Descriptions, drawings, and photographs of the morphology and anatomy of the aerial and underground fruiting structures were documented. In general, the aerial flowers in all genotypes studied were chasmogamous, allowing at least some opportunity for outcrossing. In contrast, the underground flowers were invariably much reduced, with a small, non-pigmented corolla enclosed in much-reduced, scale-like sepals. Nonetheless, anthers and viable pollen were observed in the underground flowers in all four species. With the exception of C. rotundifolium, the underground fruiting structures formed on rhizomes which initially arose either from the underground cotyledonary nodes or, in the case of G. falcata, which is epigeal, from the junction of the stem and taproot. The rhizomes gave rise to ramets when they emerged at the surface or from holes in pot bases. The V. lanceolata accessions also produced fleshy tubers which gave rise to rhizomes, especially in subsequent years. In C. rotundifolium, the geocarpic structures arose on specialised, fleshy, geotropic stems that grew down from the stoloniferous stems. In all species, the number of seeds per underground pod was fewer than in the aerial pods, and the underground seeds were invariably larger, although the extent differed between legume genotypes. There was no evidence of effects on growth or development depending on whether plants were grown from aerial or underground seeds. Some of the adaptive and agronomic implications of the key findings are discussed. In particular, it is argued that amphicarpy in the Australian species is an adaptation to seed predation, and to spatially heterogeneous inland soils.

Trifolium spumosum L. (bladder clover) is an aerial seeding annual legume that is adapted to fine-textured soils throughout the Mediterranean Basin. This article is the first of two papers that describe the process of domestication of T. spumosum as a new species to commercial agriculture. This paper describes a broad range of investigations into the ecology, agronomy and rhizobiology of this new species. Through a series of five experiments, we have tested the general hypothesis that T. spumosum accessions demonstrate a range of sought-after agronomic traits and offer an alternative to annual Medicago spp. for ley farming systems in the medium to low rainfall areas of the mixed crop/livestock zone of southern Australia.

T. spumosum presents seeds at the top of the canopy in heads that do not readily shatter, so seed can be harvested using conventional cereal harvesters instead of the specialist suction equipment required for harvest of seed from annual T. subterraneum and Medicago spp. T. spumosum was found to be relatively fecund and had high levels of biomass production in comparison to the other annual legumes that were tested. The species also demonstrated high levels of within-season hardseededness (remaining hard in summer and softening in autumn) so seedbanks would be protected from summer rainfall events. In addition, T. spumosum showed high levels of between-season dormancy, which allows the species to carry a seedbank through a cropping phase or series of poor seasons. A herbicide experiment showed that clover species varied in tolerances, with T. spumosum the least sensitive of all of the legumes tested to Flumetsulam. A cross-inoculation experiment to measure symbiotic effectiveness revealed that WSM1325 (current clover strain) surpasses WSM409 (previous strain) in its relationship with the annual clovers of contemporary interest, while being highly effective at nitrogen fixation with T. spumosum.

The results of this study and an associated investigation into feeding value indicate that T. spumosum offers a productive alternative to annual Medicago spp. on fine-textured soils. Of the T. spumosum accessions tested, the most promising has been released under the cultivar name of AGWEST Bartolo.