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MicroRNA (miRNA)-mediated regulation of auxin signaling components plays a critical role in plant development. miRNA expression and functional diversity contribute to the complexity of regulatory networks of miRNA/target modules. This study functionally characterizes two members of the rice (Oryza sativa) miR393 family and their target genes, OsTIR1 and OsAFB2 (AUXIN SIGNALING F-BOX), the two closest homologs of Arabidopsis TRANSPORT INHIBITOR RESPONSE 1 (TIR1). We found that the miR393 family members possess distinctive expression patterns, with miR393a expressed mainly in the crown and lateral root primordia, as well as the coleoptile tip, and miR393b expressed in the shoot apical meristem. Transgenic plants overexpressing miR393a/b displayed a severe phenotype with hallmarks of altered auxin signaling, mainly including enlarged flag leaf inclination and altered primary and crown root growth. Furthermore, OsAFB2- and OsTIR1-suppressed lines exhibited increased inclination of flag leaves at the booting stage, resembling miR393-overexpressing plants. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsTIR1 and OsAFB2 interact with OsIAA1. Expression diversification of miRNA393 implies the potential role of miRNA regulation during species evolution. The conserved mechanisms of the miR393/target module indicate the fundamental importance of the miR393-mediated regulation of auxin signal transduction in rice.

Flag-leaf-related traits including length (FLL), width (FLW), area (FLA), thickness (FLT), and volume (FLV) of flag leaves are the most important determinants of plant architecture and yield in wheat. Understanding the genetic basis of these traits could accelerate the breeding of high yield wheat varieties. In this study, we constructed a doubled haploid (DH) population and analyzed flag-leaf-related traits in five experimental locations/years using the wheat 90K single-nucleotide polymorphism array. It’s worth noting that a novel method was used to measure FLT and FLV easily. Leaf thickness at two-thirds of the leaf length from tip to collar represented the average leaf thickness as measured with freehand sections and was used to calculate the leaf volume. In addition, flag-leaf-related traits showed positive correlations with yield related traits under two different water regimes. A total of 79 quantitative trait loci (QTL) controlling the five traits were detected among all chromosomes except 4D and 5A, explaining 3.09–14.52% of the phenotypic variation. Among them, 15 stable QTL were identified in more than three environments, including two major QTL for FLT, six for FLW, three for FLA, two for FLT and two for FLV. DH lines with positive alleles at both QTL regions had an average FLL (9.90%), FLW (32.87%), FLT (6.62%), FLA (18.47%), and FLV (20.87%) greater than lines with contrasting alleles. QFLT-2B , QFLV-2A , and QFLV-7D were co-located with yield-related traits. The 15 QTL were validated by tightly linked kompetitive allele specific PCR (KASP) markers in a recombinant inbred line (RIL) population derived from a different cross. QFLL-4A , QFLW-4B , QFLA-5D.1 , QFLA-7A , QFLA-7D.1 , QFLT-2B , QFLT-6A , QFLV-2A , and QFLV-7D are likely novel loci. These results provide a better understanding of the genetic basis underlying flag-leaf-related traits. Also, target regions for fine mapping and marker-assisted selection were identified and these will be valuable for breeding high yielding bread wheat.

BACKGROUND: Flag leaf is the most essential organ for photosynthesis in rice and its size plays an important role in rice breeding for ideal plant-type. Flag leaf size affect photosynthesis to a certain extent, thereby influencing rice production. Several genes controlling leaf size and shape have been identified with mutants. Although a number of quantitative trait loci (QTLs) for leaf size and shape have been detected on 12 chromosomes with different populations of rice, few of them were cloned. RESULTS: The pair-wise correlation analysis was conducted on length, width and length-width ratio of the flag leaf, and yield per plant in the core recombinant inbred lines of Liang-You-Pei-Jiu (LYP9) developed in Hainan and Hangzhou. There were significant correlations among the three flag leaf size and shape traits. Interestingly, a positive correlation was found between flag leaf width and yield per plant. Based on the high-resolution linkage map we constructed before, 43 QTLs were detected for three flag leaf size and shape traits and yield per plant, among which 31 QTLs were unreported so far. Seven QTLs were identified common in two environments. And qFLW7.2, a new major QTL for flag leaf width, was fine mapped within 27.1 kb region on chromosome 7. Both qFLW7.2 and qPY7 were located in the interval of 45.30 ~ 53.34 cM on chromosome 7, which coincided with the relationship between yield per plant (PY) and flag leaf width (FLW). CONCLUSION: qFLW7.2, which explained 14% of the phenotypic variation, increased flag leaf width with 93–11 allele. Two candidate genes were selected based on sequence variation and expression difference between two parents, which facilitated further QTL cloning and molecular breeding in super rice.

Grain yield is a quantitative trait, which is determined by several agronomic traits. Unfortunately, there is little information about the genetics behind yield components in US rice cultivars. The objectives of the present study were to (1) conduct a QTL study to identify chromosome (chr. hereafter) regions associated with yield traits in two U.S.-developed rice cultivars and (2) identify candidate genes in major QTL regions related to yield traits. Four rice cultivars were evaluated in summer 2017 at the University of Arkansas System Division of Agriculture's Rice Research and Extension Center (RREC) at Stuttgart, AR. for 15 agronomic traits associated with yield. Of the four cultivars, \"LaGrue\" had a higher number of seeds/panicle, number of primary panicle branches/panicle, and number of seeds/plant and \"Lemont,\" despite having longer panicles and higher 100 seed weight/panicle, produced the least number of seeds among the cultivars. A bi-parental population was developed from a cross between LaGrue and Lemont for QTL analysis. A set of 322 F2:3 lines were evaluated in a randomized complete block design (RCBD) for several agronomic traits at two locations with three replications for each line. A total of 17 major QTL were detected, including two major QTL for plant height on chr. 1 and two major QTL for flag leaf length and panicle length on chr. 8 with seven candidate genes found in these regions. The results from the study would be useful for marker-assisted selection in rice breeding.

Over the course of two winter periods, researchers at the Agricultural Experiment Unit, College of Agricultural Engineering Sciences, University of Baghdad, studied the effects of covering wheat (the Al-Furat variety) and “vitamins B9” (“folic acid”) and E “(tocopherol)” on a number of growth traits. Three independent trials were conducted utilizing a factorial design within a Randomized Complete Block Design. The first component was folic acid at 0, 250, and 500 mg L-1; the second component was vitamin E at 0, 1, and 2 ml L-1. At the start of the tillering and flowering stages, both vitamins were applied. All measured characteristics (plant height, flag leaf area, total tiller count, plant dry weight at booting and 100% blooming phases, and “vitamin B9” 500 mg L-1) were found exceeded at this dosage. Aside from that, total chlorophyll, chlorophyll a and b content in leaves, and the pace of crop growth.Since the focus of 2 ml L-1 was higher than most of the attributes, applying vitamin E influenced the growth characteristics. The number of tillers, plant dry weight, crop growth rate, total chlorophyll, biological yield, chlorophyll a and b  in leaves.

The outcrossing traits in rice (Oryza sativa L.) affect the yield of hybrid seed production. Using a cytoplasmic male sterile (CMS) line with good outcrossing traits, such as short flag leaf length (FLL), narrow flag leaf width (FLW), wide flag leaf angle (FLA), and elongated panicle neck length (PNL), for hybrid rice seed production, it is possible to avoid the procedure of cutting flag leaves and make the supplementary pollination feasible by machine. In this study, a japonica restorer C-bao as the receptor parent and a primitive japonica accession Ludao as the donor parent were used to construct a chromosome segment substitution line (CSSL) population. The CSSL population was used to detect quantitative trait loci (QTLs) for the four outcrossing traits using a likelihood ratio test based on the stepwise regression (RSTEP-LRT) method. The CSSL population constructed consisted of 163 lines covering 90.7% of the donor genome. Among the seven QTLs detected in the CSSL population, four QTLs were detected in both years. qFLL-4 explained 6.70% of the two-year-averaged phenotypic variance, and the alleles from Ludao decreased FLL 5.1 cm. qFLA-1.1 and qFLA-1.2 explained 7.85% and 21.29% of the 2-year-averaged phenotypic variance respectively, and the alleles from Ludao increased FLA 17.38° and 31.50°. qPNL-8 explained 8.87% of the 2-year-averaged phenotypic variance, and the alleles from Ludao increased PNL 4.44 cm. These favorable alleles identified could be used to improve the outcrossing traits of parents for hybrid rice seed production in rice.

Plastic film mulching often increases the yield of winter wheat in the Loess Plateau of China, but the physiological mechanisms are unclear, especially in response to the interaction between mulch and water supply. In this study, we investigated the interactive effects of initial soil water (dry, moderate, and wet), soil cover (plastic mulch, bare soil), and seasonal conditions on the dynamics of dry matter partitioning, water-soluble carbohydrates (WSC), and flag leaf senescence, and their relations with yield and its components. Plastic mulch increased dry matter accumulation at anthesis and maturity relative to bare soil, with no interaction with season or initial soil water. Allocation of dry matter to leaf, stem, and spike did not change with soil cover. Compared with bare soil, mulch increased WSC accumulation by 14% at anthesis and its translocation by 16%. Soil cover did not influence the senescence of flag leaf after anthesis as indicated by similar dynamics of the C:N ratio. Grain yield was higher under plastic mulch than bare soil in two out of three seasons, and was associated with a higher translocation amount of WSC and post-anthesis dry matter that linked grain weight, grain number, and harvest index.

A field experiment was conducted at the Agricultural Experiment Unit, College of Agriculture Engineering Sciences, University of Baghdad, during two winter seasons 2016-2017 and 2017-2018 to study the response of some growth traits for wheat Cv. Al forat to foliar spraying using with humic glutamic acid and acid. A factorial experiment was with in Randomized Complete Block Design applied three replications, it involved two factor ,first factor was glutamic acid with three concentrations (0,250,500) mg L-1, second factor was humic acid with three concentrations (0,1,2) ml L-1, have been sprayed at tillering and flowering stages. The results showed that all the studed growth traits (plant height, ,number of tillers, flag leaf area dry weight for plant , crop growth rate ,relative growth rate and biological yield) were affected by spraying with humic acid and glutamic acid for two season concentration , 2ml -1 from humic acid was superior on most of studies traits , as for glutamic acid ,plants treated with concentrations 250 and 500 mg L-1 were produced the highest mean for studies traits but without significant difference between them in some traits .The interaction between two factors was significant on most studies growth traits .

A field experiments were carried out at Abu- Graib Research Station- Agricultural Research Office- Ministry of Agriculture during 2014- 2015 season to investigate the performance of 225 pure lines of bread wheat (Triticum aestivum L.), which at sixth generation after crossing among local and exotic genotypes (during 2008 to 2014) with their parents. The experiment was conducted using Simple Lattice Design with three replications. The results were revealed highly significant differences among genotypes for all studied traits. The genotypes 39 and 192 had higher number of days to 50% flowering (140 days), the longest period of physiological maturity 159 days of genotype 49. The highest means of flag leaf area (80.4 cm2) were found by genotype 199, the genotype 101 gave higher flag leaf angle (720), the genotype 28 gave higher plant height (94.6 cm), higher number of tillers (47.4 tillers) produced by genotype 99, genotype 207 gave higher length of spike (19.3 cm). The genotype 156 superior in number of spikelet spike-1 and highest proline content (6.91 μ moles mg-1) in flag leaf was found in genotype 39.

Contribution to yield of cereals has traditionally been studied using yield and various yield components, thus neglecting the role of other organs such as ear awns and flag leaf. Here, we studied the effects of genotypes on the photosynthetic activity of the flag leaf blade and the ear awns of spring wheat. The parameters related to the photosynthetic activity were analyzed in relation to the grain yield and various yield components at maturity. In the present study, ten wheat varieties/lines were tested to find out the effects of flag leaf and ear awns detachment on grain yield. There was much genetic variability among different varieties/lines for different traits. Awns detachment exhibited less effect on yield and yield related characters as compared to flag leaf detachment, while detachment of both had more significant effects than individual treatment. Flag leaf area and some other components showed positive and significant correlation with grain yield. Which suggested that flag leaf + awns might be used a morphological marker, while selecting wheat varieties/lines for good photosynthetic activity and high yield.