Although many interspecific crosses in Cicer species have successfully been carried out to improve the population in cultivated chickpea (Cicer arietinum L.), interspecific and backcross populations derived from mutants of Cicer species have not been studied for revealing suppressed genes responsible for heterotic effects and transgressive segregations. Therefore, the study aimed (i) to estimate heterosis (here, offspring superior to mid-parent value) and heterobeltiosis (offspring superior to better parent) for yield and yield components in the F1; (ii) to decipher transgressive segregation (extreme phenotypes) in F2 and backcross populations; and (iii) to reveal suppressed genes in interspecific and backcross populations (C. arietinum × F1 and C. reticulatum Ladiz.× F1) derived from interspecific crosses between a mutant of C. arietinum and a mutant of C. reticulatum. Heterobeltiosis was found for seed and biological yields, number of branches, and number of pods per plant in F1 progeny; heterosis was determined for the additional traits of 100-seed weight and harvest index. Heterobeltiosis and heterosis for yield and yield components in F1 progeny prompted transgressive segregation for these traits in F2 and backcross populations. In the backcrosses, C. arietinum × F1 crosses produced greater seed size and more pods per plant than C. reticulatum × F1, suggesting that C. arietinum × F1 backcrossing could improve yield components and lead to large seed size. Most of the high-yielding progeny in F2 and C. arietinum × F1 populations had double-podded nodes. It was concluded that the suppressed genes in a mutant of C. reticulatum or a mutant of C. arietinum played a crucial role in increasing transgressive segregations and allowing the cultivated chickpea to gain increased yield and yield components as well as large seed size.

Oats likely emerged as part of the weedy grass assemblage in early wheat and barley crops. Some Avena species, such as A. fatua and A. sterilis, evolved into aggressive weeds, and the high interspecific competitive ability of cultivated oats (A. sativa) is valued agronomically to facilitate weed control in rotations. We tested the hypothesis, verified in many crops, that high yield of oats is related to low intraspecific competitive ability. Ten contemporary oat varieties, selected for grain yield and milling attributes, where grown in three environments. Response to competition was calculated as 100 × (Yb – Yc)/Yc, where Y is yield measured in border (b) and centre (c) rows. The same definition was used to calculate response to competition of yield components (biomass, harvest index, grain number, grain weight) and the components of grain number (panicle number and grains per panicle). Yield response to competition was affected by all three sources of variation, i.e. environment, variety and variety × environment interaction. The interaction demonstrates the plasticity of yield response to intraspecific competition; for example, the response to competition of variety Mortlock varied from 9% to 71% among environments. This plasticity in yield response to competition was partially related to variety-dependent responses to competition for biomass and harvest index, number of panicles and number of grains per panicle. We did not find the expected negative association between yield and variety-dependent response to competition. We discuss how this lack of correlation could relate to sampling issues, i.e. a limitation in the range of environments and varieties explored in this study, or reflect a legitimate feature of oat crops arising from early and contemporary selective pressures.

Echium plantagineum is a significant pasture weed in the Mediterranean climatic zone of several countries, including Australia. This invasive weed, introduced as an ornamental into Australia (where it is known as Paterson’s curse), quickly became established and is now a significant weed of agriculture. Although E. plantagineum is a well-established, highly competitive weed that thrives under disturbance and is tolerant of a wide variety of conditions, including varying soil moisture and drought, and some aspects of its ecology remain unknown. This study investigated germination response to temperature and light, pH, soil moisture, salinity, and pre-germination exposure of seed to heat and smoke. Temperature was found to be more influential on germination than light and the species is tolerant to a wide range of pH. However, available moisture may limit germination, as may elevated salinity. Management of this weed requires approaches that minimise soil seedbank input or prevent germination of soil seedbanks.

Based on biomass composition of plants collected from saline habitats, Phragmites karka (Retz.) Trin. ex Steud. has emerged as a suitable feedstock for biofuel. In the present study, plant growth, eco-physiological responses and bioenergy characteristics of P. karka grown under conditions ranging from non-saline to ~80% seawater salinity are reported. Moderate salinity (NaCl at 100 mol m–3) increased plant fresh weight (20%), number of leaves (25%) and specific plant length, which were directly linked with increased net photosynthetic rate (25%) and stomatal conductance (25%) compared with the non-saline control. Higher photosynthetic efficiency was achieved by increasing electron transport rate (ETR, 20%), effective quantum yield (YII, 21%) and maximum efficiency of photosystem II (Fv/Fm, 20%). Decreased non-photochemical quenching (Y(NPQ)) and malondialdehyde content (18%) indicated an oxidative balance, which was also reflected in total carotenoids and chlorophylls. These eco-physiological parameters worked together to increase cellulose (34%) and hemicellulose (70%) at NaCl concentrations up to 200 mol m–3. Decreased growth under higher salinity could be linked with photosynthesis inhibition, due to stomatal closure and co-occurring reduction in CO2 uptake. Lower stomatal conductance increased water-use efficiency but led to over-production of reactive oxygen species, which disturbed oxidative stability (increasing ETR/PN) and imposed membrane leakage. Consequently, plants accumulated more carotenoids and soluble carbohydrates to stabilise PSII machinery (Fv/Fm, YII and Y(NPQ)), and to survive under high salinity. Such adaptations, however, led to growth penalty and reduced quality of lignocellulosic biomass. The above findings suggest that P. karka qualifies as a suitable raw material for biofuel under moderate salinity.

Agronomic biofortification by seed treatments is a convenient way to harvest improved yields of micronutrient-enriched grains. This 2-year field study was conducted to evaluate the effects of seed priming with zinc (Zn), boron (B) and manganese (Mn) alone and in combinations on stand establishment, grain yield and biofortification of bread wheat (Triticum aestivum L.). Seeds of wheat cv. Faisalabad-2008 were soaked in aerated solutions of 0.5 m Zn, 0.01 m B and 0.1 m Mn, alone and in different combinations, for 12 h. Seed priming with the micronutrients was quite effective in improving stand establishment, yield-contributing traits, grain yield, and straw and grain micronutrient contents during both years. Best stand establishment was achieved from seed priming with Zn+B, followed by seed priming with Zn+Mn. Grain yield improvement from different seed priming treatments was in the order Zn+B > Zn+Mn > Zn > B > Mn > Zn+B+Mn, with respective increases of 34%, 33%, 21%, 19%, 18% and 8% relative to untreated seeds. Seed priming with Zn, B and Mn alone and in combinations also improved the contents of the respective micronutrients in straw and grain. All seed priming treatments were economically profitable except Zn+B+Mn, which was not cost-effective. The highest benefit : cost ratio accrued from seed priming with Zn+B. In conclusion, seed priming with micronutrients was generally cost-effective in meeting the crop micronutrient requirements, and in improving crop stand, grain yield and grain micronutrient contents in bread wheat. Seed priming with Zn+B was the most effective in this regard.

Narbon vetch (Vicia narbonensis L.) is a promising forage legume with good resistance to cold and drought. The assessment of genetic diversity of Narbon vetch is an essential component in germplasm management. In this study, we analysed the genetic diversity of 13 local and introduced Narbon vetch accessions from three continents using 27 morphological traits and 13 simple sequence repeat (SSR) markers. Significant differences among accessions for morphological and phenological traits were observed. The SSR markers showed a total of 126 alleles with a mean number of two alleles per locus. Polymorphic information content values were in the range of 0.772–0.915 with an average of 0.858. A high level of diversity (Nei’s genetic differentiation index of 59) was observed among accessions. Analysis of genetic distances separated the studied accessions into three groups based on both morphological and SSR markers. Cluster analysis of the SSR markers separated the accessions into three groups according to geographical origin. The Tunisian populations shared the same morphological traits but differed genetically from each other and were similar to those from Lebanon. A significant correlation was detected between morphological traits and SSR markers. The results suggested that SSR markers can be used to efficiently distinguish Narbon vetch accessions and estimate their genetic diversity.

The genetic basis of physiological responses to drought and its association with productivity, persistence and summer dormancy is not clear in orchardgrass (Dactylis glomerata L.). Thirty-six orchardgrass genotypes were evaluated under water stress and non-stressed conditions during 2 years (2013–14). High genotypic variation was observed for all of the agronomic and physiological traits. Water stress reduced dry matter yield, relative water content and chlorophyll content while significantly increasing carotenoids, water-soluble carbohydrates, proline and chlorophyll a : b ratio. The results indicated that carotenoids and proline accumulation could not be used for discriminating drought-tolerant genotypes of orchardgrass, whereas water-soluble carbohydrates may be used to achieve this purpose. Moreover, the results showed that the stable genotypes that have lower changes in productivity from normal to water-stress environments also have more persistence. No association was found between summer dormancy and drought tolerance measured by both physiological and yield-based drought-tolerance indices. Some of the drought-tolerant genotypes had relatively high persistence and better autumn recovery, a characteristic useful for the development of new synthetic varieties.

The selection of cultivars with high carotenoid content represents a novel goal in the genetic improvement of oilseed rape. The successful development of an efficient method for the quantification of carotenoids in oilseed rape is a prerequisite for this breeding initiative. In the present study, ultrasound-assisted extraction was combined with a spectrophotometric method to quantify seed carotenoid levels in oilseed rape. The key variables were optimised as follows: the solvent used was a 1 : 1 (v : v) mixture of petroleum ether and acetone, the solid to solvent concentration was 0.08 g/mL, the ultrasound frequency and power were set at 45/100 (kHZ/w), and three extractions of 15 min each were performed. Compared with the conventional solvent extraction method, the time required for extraction using the ultrasound-assisted extraction method was significantly shortened (by 24 times), and the reproducibility was also remarkably improved. These results indicate that ultrasound-assisted spectrophotometric quantification is a rapid, accurate, simple and low cost tool for the screening and selection of rapeseed cultivars with high carotenoid content.

Knowledge on the growth of rice (Oryza sativa L.) in low-fertility field conditions is essential to ensure their sustainability and enhance productivity. The key variables determining the productivity of such systems were studied in 40 recommended rice varieties grown in a low-fertile field. The paddy field had received no form of fertiliser or straw for the past 40 years, but it was used for rice cultivation two times per year under other standard crop-management practices. Harvests were made at 6 weeks after planting and at physiological maturity. The same varieties were also grown for 14 days in glass boxes containing distilled water only. Stepwise regression was used to identify the important variables for predicting dry weight (DW) at 14 days, 6 weeks and maturity. Thousand-seed weight and seed phosphorus (P) content of seed paddy (grains used for planting) had strong positive correlations with DW of seedlings after 14 days (r = 0.91, P < 0.0001) and 6 weeks (r = 0.7, P < 0.0001), respectively. However, initial growth performances did not correlate well with aboveground DW or grain yield at maturity. DW at maturity positively correlated with time taken to maturity (r = 0.78, P < 0.0001), shoot K content (r = 0.28, P = 0.008), root DW (r = 0.22, P < 0.02), and uptake rates of K (r = 0.32, P < 0.01) and P (r = 0.33, P < 0.01) at 6 weeks. Seed N concentration decreased (r = −0.63, P < 0.001) and growth rate increased (r = 0.65, P < 0.001) with time taken to maturity. Although seed weight and seed P content of rice are key determinants of early crop establishment, capacity to produce large roots, amount of K taken up, P and K uptake rates at 6 weeks, and time taken to maturity are the key determinants of maturity biomass and grain yield in low-fertile field conditions.

Field and glasshouse experiments confirmed the occurrence of boron (B) deficiency in subterranean clover (Trifolium subterraneum L.) pasture in eastern Victoria. Diminished productivity was linked to the small-seededness of clover and the poor effectiveness of clover root-nodule bacteria (rhizobia, Rhizobium leguminosarum bv. trifolii). Productivity, especially of clover and clover seed, increased following applications of up to 6 kg B ha–1 (P B deficiency in the nodulated legume induced conditions within the plant and or its rhizobia that led to impaired nitrogen (N2) fixation. Glasshouse research indicated that populations of soil-borne rhizobia taken from B-deficient soils were poorly effective in N2 fixation and that rhizobia from soils growing subterranean clover cv. Leura were significantly less effective (P Additionally, subterranean clover seed generated in B-deficient soils was at least one-third smaller than the seed of commercial seed but responded to inoculation with effective rhizobia. This indicated that any symbiotic malfunction of clover from B-deficient soils was not due to an inability to respond to nitrogen per se. On the other hand, cv. Leura from B-deficient soils fixed significantly less N2 than commercial cv. Leura when each was inoculated with rhizobia from B-deficient soils.