Salinity and drought are major abiotic stresses affecting wheat (Triticum aestivum L.) production throughout the world, and discovery of loci for traits affecting yield under salinity may lead to the breeding for salt-tolerant plants. In the present study, 186 F₁₀ recombinant inbred line (RIL) populations were evaluated under salt-stress conditions in order to identify main-effect and epistatic-effect quantitative trait loci (QTLs) for 15 traits in wheat during the germination and early-seedling stages. In total, 61 main-effect QTLs on 15 chromosomes and 21 epistatic interactions on 12 chromosomes were detected through composite interval mapping (CIM) and a mixed-model-based CIM method. Two major QTLs for primary-leaf fresh weight and coleoptile fresh weight were detected on chromosome (or linkage group) 5B₂ and 2D, respectively, which contributed ∼44% and 43% of the phenotypic variance. Additionally, 12 QTL clusters including different traits were detected on 1A₁, 3A, 4A, 2B₁, 3B, 5B₁ and 2D₁. Candidate genes were identified within QTL regions and gene ontology (GO) enrichment analysis was performed. In total, 9134 candidate genes were grouped into 274 GO terms (including 79 GO terms involved in the ‘biological process’ category). These genes directly or indirectly play a vital role such as lipid localisation, biological regulation, fatty acid biosynthetic process, cellular process, DNA conformation change, translational elongation, carbohydrate metabolic process, Fe ion homeostasis, hydrogen peroxide metabolic process, and pigment biosynthetic process at the germination and early-seedling stages under salt-stress conditions.

The B-BOX (BBX) proteins are an important class of zinc-finger transcription factors involved in the regulation of plant growth and development, and have been identified in many plant species. However, there is no systematic study of common wheat (Triticum aestivum L.) BBX genes. Through comprehensive bioinformatics analysis, we identified and characterised 96 BBX genes from wheat, and provided the genes with a unified nomenclature. We describe the chromosomal location, gene structure, conserved domains, phylogenetic relationships and promoter cis-elements of TaBBX family members. The expression patterns under different conditions, especially under different hormones and light–dark conditions, were studied in detail. According to the diversity of conserved domains, we divided TaBBX proteins into five subfamilies. Gene-duplication analysis showed that duplication of chromosome segments was the main reason for the expansion of the TaBBX gene family. Detecting the expression profiles of six TaBBX genes in different tissues by quantitative real-time PCR, we found that the six genes are regulated under light–dark treatment, and that some TaBBX genes (TaBBX2.11, TaBBX2.13, TaBBX2.15 and TaBBX3.10) are strongly induced by the plant hormones abscisic acid, indole-3-acetic acid and salicylic acid. Our analysis of wheat BBX genes at the genomic level will provide a solid foundation for further identifying the functions of specific genes in light stress responses.

We hypothesised that mixing of rice lines with different maturity dates can improve the productivity per unit area while improving lodging resistance on account of the heterogeneous canopy. To test this hypothesis, we grew two lines, wild-type (WT) and early-maturing (EML), of each of two cultivars (Koshihikari and Hitomebore) in monoculture plantings and within-cultivar mixed plantings, with WT and EML plants alternating every one or two rows, over 2 years in northern Japan. The mixtures formed a canopy with different heading dates (5–7 days earlier than WT in Hitomebore and 14–19 days earlier in Koshihikari). For Koshihikari, the mixture increased grain yield per plant in the WT by 18–33%, but decreased it in the EML by 19–22%; however, for Hitomebore, there was no significant difference. Consequently, grain yield per unit area did not change relative to the mean of monocultures of WT and EML in either cultivar. Lodging tolerance improved significantly in the mixtures, especially for Koshihikari. Thus, mixing rice lines with different maturity dates improved lodging tolerance without decreasing productivity.

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is a common disease of soybean (Glycine max (L.) Merr.) worldwide, seriously affecting yield. Kangxian 2 is a soybean variety with a high level of resistance to H. glycines (HG) Type 0 (SCN race 3) and a yellow seed coat. However, we know little about the mechanism of resistance to HG Type 0 in Kangxian 2. In this study, we used the Illumina HiSeq high-throughput sequencing platform to analyse the transcriptome of Kangxian 2 and obtained 65.74 Gb clean data. Transcriptional changes in Kangxian 2 caused by HG Type 0 stress after 0–10 days are described. Kangxian 2 showed different levels of gene expression after inoculation, and under HG Type 0 stress after different times. Overall, 6854 HG Type 0-induced genes and 5328 HG Type 0-repressed genes were found to be differentially regulated. The greatest number of differential genes annotated to cellular process, metabolic process, single-organism process, binding, catalytic activity and other pathways. In addition to findings of differentially expressed genes similar to other published work, such as the regulation of biosynthesis of many secondary metabolites, carbon sequestration of photosynthetic organisms, other types of O-polysaccharide biosynthesis, phenylpropane biosynthesis, pyruvate metabolism and other pathways, this study also revealed the differential regulation of genes related to the diarylheptanoid and gingerol biosynthesis pathway and found some metabolic pathways that were specifically expressed in the syncytial initiation and establishment stages. Gene expression analyses using real-time fluorescence quantitative PCR showed that the expression of GmMADS and GmTUB changed strongly after 7 days and 10 days of HG Type 0 stress compared with the control. We conclude that GmMADS and GmTUB transcription factor genes may play an important role in the resistance of Kangxian 2 to HG Type 0 stress.

In rotationally grazed pastures, the canopy light environment can be modulated through both grazing frequency and severity, and the magnitude of sward responses may differ according to forage species and its ability to use available resources. We hypothesised that the tall, tufted, fast-growing, tussock-forming species Mombaça guineagrass (Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L.Jacobs cv. Mombaça) can modulate its tillering dynamics and change its persistence pathway according to grazing strategy and the availability of growth factors. Treatments corresponded to all combinations of two levels of pre-grazing canopy light interception during regrowth (95% and maximum) and two post-grazing heights (30 and 50 cm), and were allocated to experimental units according to a randomised complete block design with four replications. Measurements were performed throughout contrasting climatic conditions during four seasons from January 2001 to February 2002. A quite stable tiller population density presented regardless of the range of grazing frequency and severity used in the study. However, tiller appearance and death were strongly influenced (P < 0.001) by season of the year, with highest rates recorded during the two summers and lowest during autumn–winter. There was no conclusive evidence that the persistence pathway of Mombaça guineagrass changes within the grazing management strategies studied.

For tropical forage grasses, leaves are the main morphological component accumulated at the beginning of regrowth, and as leaf area index increases, plants change their growth pattern, allocating more resources to stem elongation as a means of optimising light capture. We hypothesised that, for Mombaça guineagrass, stem elongation and leaf senescence rate play a major role in determining net herbage accumulation rate (NHAR) and that senescence would be the key factor driving the reduction in NHAR when regrowth is interrupted beyond the critical leaf area index, that is, when canopy light interception (LI) exceeds 95%. Treatments corresponded to all combinations of two levels of pre-grazing canopy LI during regrowth (LI_95% and LI_Max) and two post-grazing heights (30 and 50 cm), and were allocated to experimental units according to a randomised complete block design with four replications. Measurements were performed throughout contrasting climatic conditions during four seasons from January 2001 to February 2002. Overall, spring and the two summers were the seasons when rates of leaf appearance, leaf elongation and leaf growth rate were higher, and leaf lifespan was smaller; the inverse occurred during autumn–winter. Despite the lack of statistically significant differences in NHAR between LI treatments during some seasons of the year, the ratio of leaf growth rate to NHAR was consistently higher for LI_95% than LI_Max. The pre-grazing target of LI_95% was also efficient for decreasing stem elongation and leaf senescence rate. Increased senescence on individual tillers was the key driver generating modifications in the patterns of variation in NHAR beyond the critical leaf area index, suggesting that there is no advantage in extending the regrowth period when the main objective is to maximise leaf growth rate or NHAR.

Frequency and intensity of floods and the extent of salt-affected lands are expected to increase in pastures and grassland ecosystems as a result of global climate change. This study evaluated the effects of waterlogging, salinity (150 mm NaCl, ∼15 dS m^–1) and their combination over 14 days of treatment on morphological and growth traits of seven cultivars of Festuca arundinacea (tall fescue). Recovery was also assessed after a 14-day growth period under aerated, non-saline conditions (recovery phase). All cultivars survived the imposed stresses, showing greater tolerance to waterlogging than to salinity or the combined stress, evaluated as a response ratio of total dry mass relative to the control. The combined stress provoked growth lower than predicted by a multiplicative model in one cultivar, growth equal to the model in three cultivars and growth higher than the model in three cultivars. High variability among cultivars in response to each stress and phase was observed; this was more evident for relative growth rate of roots than of shoots. Plant morphological traits were affected by treatments in different ways; mature tiller weight was maintained, and tiller number decreased by 79–71% under waterlogging and combined stresses, whereas the opposite responses occurred under salinity. During the recovery phase, plants in all stress treatments had lower tiller numbers than controls and prioritised the growth of pre-existing tillers, which were heavier. Number of dead leaves per plant increased in saline and combined treatments. In general, F. arundinacea proved more tolerant to waterlogging than to salinity or combined treatments, and showed promising variability among cultivars with respect to root relative growth rate under the evaluated stresses, which can be used in future breeding programs. The findings also provide a basis for further research into the tolerance mechanisms involved.