Vigorous Early Growth Research Articles

Influence of Potting Mixture and Sowing Orientation on Physiological Parameters of Balanites roxburghii (Linn.)

Balanites roxburghii (Linn.) species has been classified under the category of endangered plant species due to excessive exploitation for a variety of purposes, which has necessitated conservation of this tree species, and hence a study was conducted to investigate the effect of potting mixture and sowing orientation on early growth performance and vigour. Seeds were subjected to seven potting mixtures: M1: Soil:Sand:FYM 2:1:1, M2: Soil:Cocopeat:FYM 2:1:1,M3: Soil:Cocopeat:Vermicompost 2:1:1, M4: Soil:Paddy Husk:FYM: 2:1:1, M5: Soil:Paddy Husk:Vermicompost: 2:1:1, M6: Soil: Saw Dust:FYM 2:1:1, and M7: Soil:sawdust: Vermicompost 2:1:1. The seeds were sown in three orientations. S1: Seeds laid vertically with stalk end downwards; S2: Seeds laid horizontally and S3: Seeds laid vertically with stalk end upwards. Physiological parameters considered for assessment were seed germination, days taken for germination, seedling length, and seedling vigor index. A completely randomized design was used for the experiment. The results showed that there is a significant difference among seven different potting mixtures and three orientations. At the end of 8 weeks, the seed is sown horizontally in the potting mixture Soil:cocopeat:vermicompost (2:1:1) has recorded the germination percentage of 71.67%, 37 days taken for seed germination, highest seedling length (64 cm), and highest seedling vigour index (4561). The high-vigor seedlings may survive even in unfavorable conditions, with high survival rate compared to others. The study recommended that to obtain high-vigor Balanites roxburghii seedlings, seeds may be sown in potting mixture soil: cocopeat: vermicompost (2:1:1) with horizontal orientation.

EVALUATION OF SPRING WHEAT GENOTYPES UNDER WATER STRESSED CONDITION

Pakistan faces severe challenges in wheat production annually due to the devastating effects of drought stress. Therefore, present research was carried out to evaluate 15 exotic bread wheat genotypes along with the local check variety, Khirman for their performance under drought stress. Analysis of variance revealed that all the traits were significantly different (P<0.01) among the cultivars. Based on mean performance, genotype V-18 showed better performance for all the studied characters, while genotype V-14 showed desirable performance for different traits such as early growth vigor, number of grains spikelet-1, number of grains spike-1, number of spikelets spike-1, spike length, peduncle length, and grain yield plant-1. The local check Khirman also produced desirable values for four different traits, namely early growth vigor, number of grains spike-1, peduncle length, and grain yield plant-1. The cluster analysis divided all the genotypes into three distinct clades. The first cluster comprises V-14, V-18, and the local check Khirman, which performed very well under drought conditions compared to the other genotypes. The presence of these genotypes with the local check Khirman is regarded as indicative of drought-tolerant genotypes. The second cluster comprises nine genotypes, namely V-10, V-11, V-12, V-13, V-16, V-19, V-20, and V-23, which performed moderately compared to the genotypes found in the drought-tolerant cluster. The last cluster comprises four genotypes, namely V-09, V-15, V-17, and V-22, which performed very poorly under drought conditions. Overall, the two exotic lines, V-14 and V-18, which were in the cluster with the drought-tolerant variety Khirman, performed very well and can be considered as drought-tolerant genotypes

A Novel Function of GW5 on Controlling the Early Growth Vigor and its Haplotype Effect on Shoot Dry Weight and Grain Size in Rice (Oryza sativa L.)

Strong early growth vigor is an essential target in both direct seeded rice breeding and high-yielding rice breeding for rice varieties with relatively short growth duration in the double-cropping region. Shoot dry weight (SDW) is one of the important traits associated with early growth vigor, and breeders have been working to improve this trait. Finding stable QTLs or functional genes for SDW is crucial for improving the early growth vigor by implementing molecular breeding in rice. Here, a genome-wide association analysis revealed that the QTL for SDW, qSDW-5, was stably detected in the three cultivation methods commonly used in production practice. Through gene-based haplotype analysis of the annotated genes within the putative region of qSDW-5, and validated by gene expression and knockout transgenic experiments, LOC_Os05g09520, which is identical to the reported GW5/GSE5 controlling grain width (GW) and thousand grain weight (TGW) was identified as the causal gene for qSDW-5. Five main haplotypes of LOC_Os05g09520 were identified in the diverse international rice collection used in this study and their effects on SDW, GW and TGW were analyzed. Phenotypic comparisons of the major haplotypes of LOC_Os05g09520 in the three subpopulations (indica, japonica and aus) revealed the same patterns of wider GW and higher TGW along with higher SDW. Furtherly, the haplotype analysis of 138 rice varieties/lines widely used in southern China showed that 97.8% of the cultivars/lines carry Hap2LOC_Os05g09520. These results not only provide a promising gene source for the molecular breeding of rice varieties with strong early growth vigor, but also elucidate the effect of the LOC_Os05g09520 haplotypes on SDW, GW, and TGW in rice. Importantly, this study provides direct genetic evidence that these three traits are significantly correlated, and suggests a breeding strategy for developing high-yielding and slender grain-shaped indica cultivars with strong early growth vigor.

Integrating NDVI, SPAD, and Canopy Temperature for Strategic Nitrogen and Seeding Rate Management to Enhance Yield, Quality, and Sustainability in Wheat Cultivation.

This study explores the interplay between nitrogen doses and seeding rates on wheat yield, biomass, and protein content. Utilizing tools such as the Normalized Difference Vegetation Index (NDVI), Soil Plant Analysis Development (SPAD) measurements, and canopy temperature (CT), we conducted experiments over five growing seasons. The treatments included three nitrogen levels (0, 60, 120 kg/ha) and three seeding rates (300, 400, 500 seeds/m2) in a split-plot design with 90 plots and two replications. Our results show that an intermediate nitrogen dose (60 kg/ha) combined with a moderate seed rate (400 seeds/m2) enhances wheat yield by 22.95%. Reduced nitrogen levels increased protein content, demonstrating wheat's adaptive mechanisms under nitrogen constraints. NDVI analysis highlighted significant growth during the tillering phase with high nitrogen, emphasizing early-stage nutrient management. SPAD measurements showed that early nitrogen applications boost chlorophyll content, essential for vigorous early growth, while CT data indicate that optimal nitrogen and seed rates can effectively modulate plant stress responses. As crops mature, the predictive capacity of NDVI declines, indicating the need for adjusted nitrogen strategies. Collectively, these findings advocate for refined management of nitrogen and seeding rates, integrating NDVI, SPAD, and CT assessments to enhance yields and promote sustainable agricultural practices while minimizing environmental impacts.

Expression Patterns Divergence of Reciprocal F1 Hybrids Between Gossypium hirsutum and Gossypium barbadense Reveals Overdominance Mediating Interspecific Biomass Heterosis.

Hybrid breeding has provided an impetus to the process and achievement of a higher yield and quality of crops. Interspecific hybridization is critical for resolving parental genetic diversity bottleneck problems. The reciprocal interspecific hybrids and their parents (Gossypium hirsutum and Gossypium barbadense) have been applied in this study to elucidate the transcription regulatory mechanism of early biomass heterosis. Phenotypically, the seed biomass, plant height over parent heterosis, leaf area over parent heterosis, and fresh and dry biomass were found to be significantly higher in hybrids than in parents. Analysis of leaf areas revealed that the one-leaf stage exhibits the most significant performance in initial vegetative growth vigor and larger leaves in hybrids, increasing the synthesis of photosynthesis compounds and enhancing photosynthesis compound synthesis. Comparative transcriptome analysis showed that transgressive down-regulation (TDR) is the main gene expression pattern in the hybrids (G. hirsutum × G. barbadense, HB), and it was found that the genes of photosystem I and Adenosine triphosphate (ATP)-binding may promote early growth vigor. Transgressive up-regulation (TUR) is the major primary gene expression pattern in the hybrids (G. barbadense × G. hirsutum, BH), and photosystem II-related genes mediated the performance of early biomass heterosis. The above results demonstrated that overdominance mediates biomass heterosis in interspecific hybrid cotton and the supervisory mechanism divergence of hybrids with different females. Photosynthesis and other metabolic process are jointly involved in controlling early biomass heterosis in interspecific hybrid cotton. The expression pattern data of transcriptome sequencing were supported using the qRT-PCR analysis. Our findings could be useful in theoretical and practical studies of early interspecific biomass heterosis, and the results provide potential resources for the theoretical and applied research on early interspecific biomass heterosis.

EXOTIC WHEAT GENOTYPES RESPONSE TO WATER-STRESS CONDITIONS

Drought is the most devastating abiotic stress which has significantly threatened global wheat production. The recent study was designed to evaluate the performance of eight exotic wheat lines through the Drought Spring Bread Wheat Yield Trial (DSBWYT), along with a local drought-tolerant check cultivar, Khirman, under water-stressed conditions based on agronomic and yield-related traits. The experiment was conducted during cropping season 2019–2020 in a randomized complete block design with three replications at the Nuclear Institute of Agriculture (NIA), Tando Jam, Pakistan. The analysis of variance revealed that there was a significant difference among the genotypes for all studied traits. The genotype DSBWYT-8 possessed better agronomic traits and growth features like early growth vigor and early ground cover. On the other hand, the genotype DSBWYT-4 performed better in yield and yield-related traits like main spike yield, grains per spike, and 1000-grains weight. Both genotype revealed excellent plot grain yield and harvest index and were not significantly different from each other. The cluster analysis grouped all the genotypes into three clades. The drought-tolerant local check cultivar Khirman clustered with genotypes DSBWYT-2, DSBWYT-4, and DSBWYT-8 thus, this clade can be regarded as drought tolerant. The second cluster comprised of two genotypes, i.e., DSBWYT-1 and DSBWYT-5, which performed relatively low as compared to genotypes present in the drought-tolerant cluster, whereas the genotypes DSBWYT-3, DSBWYT-6, and DSBWYT-7 clustered together to represent low yielding genotypes under drought condition as compared with the check cultivar Khirman. Based on these results, the genotypes DSBWYT-2, DSBWYT-4, and DSBWYT-8 can be recommended as the drought-tolerant genotypes.

Early Growth and Yield Performance at Nursery Stage of a Set of Brazilian Wild Hevea Germplasm of IRRDB Collection

A set of 55 wild Hevea brasilensis accessions from three provenances of Brazil viz., Acre (AC), Rondonia (RO) and Mato Grosso (MT), along with two popularly cultivated clones RRII 105 and RRIM 600 were evaluated for their early growth and yield performance in the first six years of growth in a nursery in the traditional rubber growing region of Kerala state, India. Relatively high clonal variability was observed for yield, while variation for girth, girth increment, single leaf area, total number of laticifer rows, diameter of latex vessels, bark thickness and crotch height ranged from medium to low. The yield ranged from 0.04 g/t/t (RO 5358) to 11.19 g/t/t (RO 5018), bark thickness from 1 mm (AC 5896) to 5.30 mm (MT 4771), total number of laticifer rows from 3 (MT 5824) to 10.67 (RO 2841) and diameter of latex vessels from 10.69 μm (AC 5487) to 21.66 μm (MT 4762). Girth ranged from 10.75 cm (AC 5896) to 35.60 cm (RO 5432) in the 6th year, while girth increment over three years ranged from 0.50 cm/year (AC 5466) to 5.47 cm/year (RO 5432), crotch height ranged from 1.88 m (RO 5364) to 5.14 m (MT 4690) and single leaf area from 37.51 cm2 (RO 5318) to 150.40 cm2 (RO 5365). The accessions were ranked using all the above parameters except single leaf area, for overall performance. Rank sum values ranged from 30 to 340 with a general mean of 194.33. Based on this study, the top 20% of the potential accessions showing early growth vigour and yield were identified which could be of use in broadening the narrow genetic base of currently cultivated genotypes and for future crop improvement programmes.

Lower seed P content does not affect early growth in chickpea, provided starter P fertiliser is supplied

Seeds of crops contain large amounts of phosphorus (P), mostly as phytate. To lower seed phytate concentration is the ultimate breeding aim and highly desirable as the benefit of humans and many animals, given seed size is not sacrificed, i.e. leading to reduced seed P content. This study tested whether low seed P content affects early chickpea growth, and whether P supply during early growth compensates for early growth from seeds with low seed P content. Twenty-three chickpea genotypes with contrasting seed P content were selected for three treatments that were compared with a control: 1) seedlings supplied with a small amount of starter P (P10), 2) one cotyledon removed to reduce P content (Remove 1), and 3) both cotyledons removed to further reduce P content (Remove 2). Genotypes with higher seed P content had more vigorous early growth than genotypes with lower seed P, as did intact seedlings compared with those cotyledons removed. Application of P fertiliser significantly enhanced early growth. Low seed P genotypes had a more economic strategy, with a greater specific leaf area and specific root length, than genotypes with medium or high seed P content. Our results provided useful information for breeders that breeding chickpea genotypes with reduced seed P, does not affect germination and seedling vigour, provided starter P is supplied at the early development stage.

Morphological and physiological factors contributing to early vigor in the elite rice cultivar 9,311

Huanghuazhan (HHZ) and 9,311 are two elite rice cultivars in China. They have achieved high yield through quite different mechanisms. One of the major features that gives high yield capacity to 9,311 is its strong early vigor, i.e., faster establishment of its seedling as well as its better growth in its early stages. To understand the mechanistic basis of early vigor in 9,311, as compared to HHZ the cultivar, we have examined, under controlled environmental conditions, different morphological and physiological traits that may contribute to its early vigor. Our results show that the fresh weight of the seeds, at germination, not only determined the seedling biomass at 10 days after germination (DAG), but was also responsible for ~ 80% of variations in plant biomass between the two cultivars even up to 30 DAG. Furthermore, the 9,311 cultivar had a larger root system, which led to its higher nitrogen uptake capacity. Other noteworthy observations about 9,311 being a better cultivar than HHZ are: (i) Ten out of 15 genes involved in nitrogen metabolism were much more highly expressed in its roots; (ii) it had a higher water uptake rate, promoting better root-to-shoot nitrogen transfer; and (iii) consistent with the above, it had higher leaf photosynthetic rate and stomatal conductance. All of the above identified features explain, to a large extent, why the 9,311, as compared to HHZ, exhibits much more vigorous early growth.

Seed Priming: An Approach to Enhance Weed Competitiveness and Productivity in Aerobic Rice: A Review

Growing rice under aerobic soil conditions is a promising water-wise technology under the context of ever-mounting water scarcity, but it is subject to poor stand establishment and high weed pressure. This invites severe competition between weeds and rice, thus reducing the crop yields on an average of 50-60 per cent. Early weed control is essential in aerobic rice. Therefore, any effort to mitigate the ill effect of crop-weed competition in the early stages of crop growth will ultimately enhance yield of aerobic rice. So, ‘seed priming’ is one of the best options to manage crop-weed competition in the early stages of crop growth. Seed priming is an approach to add moisture to seeds allowing seeds to be hydrated partially without radicle emergence Beneficial effects of seed priming such as higher germination uniformity, better allometric attributes, rapid stand establishment and vigorous early plant growth were important components for weed competitiveness in aerobic rice. Higher and synchronized emergence of primed seeds can ensure vigorous crop stand with rapid canopy development giving rice plants a preliminary advantage over weeds. Different seed priming methods/ priming agents Viz. hydro, osmo, halo, bio, solid matrix priming have been found effective in increasing the vigour and yield of aerobic rice. Therefore, seed priming is supposed to play a significant role in weed suppression. Seed priming also enhances the grain yield of rice mainly due to more vigorous seedlings resulting in earlier and enhanced resource capture, higher numbers of panicle-bearing tillers due to low mortality of seedlings, improved nutrient and moisture supply.

Genetic Analysis of Morphological Traits in Wheat Hybrids Based on the Additive-Dominance Model

Present study carried out in a randomized complete block design with three replications for determining additive, dominance and cytoplasmic effects on inheritance of yield and some of agro-morphological traits in bread wheat. The highest value of grain yield (265.5 g m–1) was obtained in p6. Dominance variance was larger than additive variance for grain-filling period (GFP), plant height (PH), spike length (SL), flag leaf exit (FLE), canopy temperature (CT), early growth vigor (EGV), grain length (GL) and thousand-grain weight (TGW). Whereas, the additive variance was larger than dominance one for days to heading (DH), days to maturity (DM), peduncle length (PL), SPAD and grain yield (GY). Therefore, for these traits selection in early breeding generations could be effective to bring positive changes in these traits. There were significantly positive additive effects (A) of P1 on GFP, CT, GL and TGW; of P3 on DH and DM; P4 on PL, FLE, SPAD and GY and of P6 on PH, SL and EGW. The crosses containing g3 × g4, g4 × g5 and g4 × g6 were indicated positive and significant heterosis for grain yield. P6 were desirable parent for reducing days to heading and maturity and increasing plant height, spike length and early growth vigor.

Remember where you came from: ABA insensitivity is epigenetically inherited in mesophyll, but not seeds

Plants transmit their experiences of environmental conditions to their progeny through epigenetic inheritance, improving their progeny’s fitness under prevailing conditions. Though ABA is known to regulate epigenetic-modification genes, no strong phenotypic link between those genes and intergenerational “memory” has been shown. Previously, we demonstrated that mesophyll insensitivity to ABA (FBPase::abi1-1{fa} transgenic plants) results in a range of developmental phenotypes, including early growth vigor and early flowering (i.e., stress-escape behavior). Here, we show that null plants, used as controls (segregates of FBPase::abi1 that are homozygote descendants of a heterozygous transgenic plant, but do not contain the transformed abi1-1 gene) phenotypically resembled their FBPase::abi1-1 parents. However, in germination and early seedling development assays, null segregants resembled WT plants. These FBPase::abi1-1 null segregants mesophyll-related phenotypes were reproducible and stable for at least three generations. These results suggest that the heritability of stress response is linked to ABA’s epigenetic regulatory effect through ABI1 and mesophyll-related traits. The discrepancy between the epigenetic heritability of seed and mesophyll-related traits is an example of the complexity of epigenetic regulation, which is both gene and process-specific, and may be attributed to the fine-tuning of tradeoffs between flowering time, growth rate and levels of risk that allow annual plants to optimize their fitness in uncertain environments.

Nutripriming with zinc sulphate and borax for early growth and seedling vigour in grain cowpea [Vigna unguiculata (L.) Walp

The experiment was conducted at Coconut Research Station, Balaramapuram with an objective to study the effect of nutripriming with ZnSO4 and borax on the early growth and seedling vigour and Zn and B content in grain cowpea. Nutripriming treatments had significant effect on germination parameters. Nutripriming with ZnSO4 either at 0.025 or 0.05 per cent recorded higher values for the germination parameters. These treatments recorded 19.68 and 18.51 per centage higher germination than control. Germination index was 1.4 times higher in seeds primed with ZnSO4 @ 0.025 and 0.05 per cent and also recorded higher values for mean daily germination and speed of germination. The highest co-efficient rate of germination and germination rate index was recorded by seed priming with ZnSO4 at 0.05 per cent and it was closely followed by ZnSO4 @ 0.025 per cent for 4 h. Nutripriming with ZnSO4 either @ 0.025 or 0.05 per cent recorded the lowest mean germination time and time to reach 50 per cent germination and also recorded higher Zn and B content. Vigour index also followed the same trend. Hence it can be concluded that nutripriming with ZnSO4 either at 0.025 or 0.05 per cent can be recommended for early seedling growth, seedling vigour and higher Zn and B content in grain cowpea.

Using Growth and Ionic Contents of Wheat Seedlings as Rapid Screening Tool for Salt Tolerance

High germination percentage with vigorous early growth is preferred for harvesting good wheat stand under saline soils. Therefore, an attempt for rapid screening of wheat genotypes for salt tolerance was made in this study. Eleven wheat genotypes including salt tolerant check Kiran-95were subjected to salinity (120 and 160 mMNaCl) along with non-saline control. Results showed a gradual decrease in seed germination and restricted seedling growth in tested wheat genotypes in response to increasing NaCl concentration in nutrient solution. Among the genotypes, NIA-AS-14-6 and NIA-AS-14-7 exhibited more sensitivity towards the salt stress at the germination stage but NIA-AS-14-6 performed quite satisfactorily later on at the seedling stage. Wheat genotypes NIA-AS-14-2, NIA-AS-14-4, NIA-AS-14-5, NIA-AS-14-10, and Kiran-95 showed better performance in term of root-shoot length, plant biomasses (fresh and dry), K+:Na+ ratio with least Na+ content, and high accumulation of K+ at higher levels of NaCl stress. On the basis of overall results, the categorization of genotypes was carried out as sensitive, moderately tolerant, and tolerant. Wheat genotypes NIA-AS-14-2, NIA-AS-14-4, NIA-AS-14-5, NIA-AS-14-10, and Kiran-95 grouped as tolerant, moderately salt tolerant group comprised of NIA-AS-14-1, NIA-AS-14-3, NIA-AS-14-6, and NIA-AS-14-8, whereas, NIA-AS-14-7 and NIA-AS-14-9 were found sensitive to salt stress. Principal component analysis revealed that components I and II contributed 70 and 16.5%, respectively. All growth parameters are associated with each other except RDW. In addition to growth traits, low Na+ and improved K+ content with better K+:Na+ ratio may be used for screening of salt tolerance in wheat as potential physiological criteria.

Low-P solution culture can be used for screening root growth vigor in soil for high nutrient uptake of spring wheat varieties

ABSTRACTPurpose: Root and root hairs of plants have been intensively studied in solution culture; however, correlation of such measurements in solution culture with development in soil is poorly understood. Therefore, the aim of this study is to study whether root and root hairs grown in solution culture can predict their behavior in soil and their correlation with macro- and micronutrients uptake of wheat genotypes.Materials and methods: The growth of roots and root hairs as well as uptake of macro- and micronutrients of six spring wheat varieties was compared in solution culture under P stress and P abundance and in a low fertility soil.Results and conclusions: Root length and surface area under P stress were significantly positively correlated with that in the low fertility soil, while no such correlation was apparent for root hair length and density. In absolute terms, the root length, surface area, root hair length and density of spring wheat varieties were substantially higher in soil than in solution culture, while the concentration and uptake of macro- and micronutrients in soil differed from solution culture in a complex way. The early uptake of macro- and micronutrients was intimately associated with root length and surface area as well as root hair length and density in soil but not in solution culture. Therefore, root length rather than root hair traits in low-P solution may be used to screen early root growth vigor in soil and thereby high nutrient uptake of wheat in low fertility soil.

Green-Sprouting of Potato Seed Tubers (Solanum tuberosum L.)—Influence of Daily Light Exposure

Pre-sprouting of potato seed tubers (Solanum tuberosum L.) in light (green-sprouting) is an established practice in short growing seasons to speed up plant development. Light exposure secures short and robust sprouts for mechanical planting. In 2014–2015, different pre-sprouting treatments were investigated, including different daily durations of light exposure during 6 to 12 weeks at 10 °C in controlled environments. The effects on sprout growth, early growth vigour and field performance in four cultivars were assessed in the greenhouse and in the field. Results indicated that the light treatments involving 8, 16 and 24 h light exposure per day all strongly inhibited sprout growth, with only minor differences between treatments. Compared to untreated tubers, within all cultivars, emergence and early plant growth was clearly and similarly accelerated by all light treatments. At harvest, cultivars were differently affected by the pre-sprouting treatments with regard to haulm senescence (greenness), tuber DM and total yield, and the latest cultivars seemed to benefit more from green-sprouting than the earliest. Different daily durations of light exposure during green-sprouting had a largely similar impact on seed tuber performance in all cultivars. Dark-sprouted tubers (de-sprouted before planting) performed largely similar to control tubers from 4 °C storage. Results demonstrate a potential for shorter daily light exposure during green-sprouting with less energy use and heating problems.

Identifying seedling root architectural traits associated with yield and yield components in wheat.

Plant roots growing underground are critical for soil resource acquisition, anchorage and plant-environment interactions. In wheat ( Triticum aestivum ), however, the target root traits to improve yield potential still remain largely unknown. This study aimed to identify traits of seedling root system architecture (RSA) associated with yield and yield components in 226 recombinant inbred lines (RILs) derived from a cross between the bread wheat Triticum aestivum 'Forno' (small, wide root system) and spelt Triticum spelta 'Oberkulmer' (large, narrow root system). A 'pouch and wick' high-throughput phenotyping pipeline was used to determine the RSA traits of 13-day-old RIL seedlings. Two field experiments and one glasshouse experiment were carried out to investigate the yield, yield components and phenology, followed by identification of quantitative trait loci (QTLs). There was substantial variation in RSA traits between genotypes. Seminal root number and total root length were both positively associated with grains m -2 , grains per spike, above-ground biomass m -2 and grain yield. More seminal roots and longer total root length were also associated with delayed maturity and extended grain filling, likely to be a consequence of more grains being defined before anthesis. Additionally, the maximum width of the root system displayed positive relationships with spikes m -2 , grains m -2 and grain yield. Ten RILs selected for the longest total roots exhibited the same effects on yield and phenology as described above, compared with the ten lines with the shortest total roots. Genetic analysis revealed 38 QTLs for the RSA, and QTL coincidence between the root and yield traits was frequently observed, indicating tightly linked genes or pleiotropy, which concurs with the results of phenotypic correlation analysis. Based on the results from the Forno × Oberkulmer population, it is proposed that vigorous early root growth, particularly more seminal roots and longer total root length, is important to improve yield potential, and should be incorporated into wheat ideotypes in breeding.

Suppression of Arabidopsis AtPUB30 resulted in increased tolerance to salt stress during germination.

The Arabidopsis U-box E3 Ub ligase AtPUB30 participates in the salt stress tolerance as a negative factor in an ABA-independent manner during germination. Based on the in silico expression data, the U-box protein 30 (AtPUB30) from Arabidopsis thaliana was identified as a gene that responds to salt stress. The deduced AtPUB30 protein consists of 448 amino acids with a single U-box motif and five ARM-repeat domains. An in vitro self-ubiquitination assay demonstrated that bacterially expressed AtPUB30 exhibited E3 ubiquitin (Ub) ligase activity and that the U-box domain was essential for the activity. Real-time qRT-PCR and promoter-GUS analyses showed that AtPUB30 was induced by high salinity, but not by drought, cold, or abscisic acid (ABA), in roots but not in shoots. These results suggest that AtPUB30 is an Arabidopsis U-box E3 Ub ligase, the expression of which is selectively enhanced by salt stress in roots. T-DNA-inserted loss-of-function atpub30 mutant plants (atpub30-1 and atpub30-2) were more tolerant to salt stress in the germination stage, as identified by radicle emergence, cotyledon opening, and more vigorous early root growth relative to wild-type plants. Thus, it is likely that AtPUB30 plays a negative role in high salinity tolerance in the germination process. Wild type and mutant plants displayed very similar germination rates when treated with ABA, suggesting that the action of AtPUB30 in the germination stage is ABA independent. The post-germination growth of NaCl-stressed wild type and mutant plants were indistinguishable. Overall, our data suggest that the Arabidopsis U-box E3 Ub ligase AtPUB30 participates in the salt stress tolerance as a negative factor in the germination stage in root tissues.

Effects of Hydro and Hormonal Seed Priming on Seed Germination of Milk Thistle under Saline Stress Condition

Salinity is an abiotic stress which has harmful effects on germination of many plants. Therefore, high germination rate and vigorous early growth under salty soils is preferred. Seed priming is a way to increase salt tolerance of plants. An experiment was conducted to investigate the effect of seed priming on germination of milk thistle under salinity condition. The treatments were 4 levels of seed priming (no priming, distilled water as hydro priming and 0.5 and 1.0 mM salicylic acid) and 5 levels of salinity (0, 40 and 80 mM NaCl and 40 and 80 mM CaCl2). The experiment arranged as a factorial in a completely randomized design (CRD) with three replications. Results showed that salinity decreased germination percentage and germination rate to about 16 and 32% in 80 mM CaCl2 level compared to control, respectively. The highest mean germination time (5.7 day) were belonged to 80 mM CaCl2. Radicle and plumule length significantly decreased by 80 mM NaCl and 40 and 80 mM CaCl2. The lowest seedling weight and seed stamina observed in 80 mM CaCl2. 0.5 mM salicylic acid improved all traits except mean germination time as compared to control. Salicylic acid (0.5 mM) improved radicle length under 0, 40 and 80 mM NaCl salinity levels as well as increased plumule length at the 0 and 40 mM NaCl salinity conditions.

Effects of Hydro and Hormonal Seed Priming on Seed Germination of Milk Thistle under Saline Stress Condition

Salinity is an abiotic stress which has harmful effects on germination of many plants. Therefore, high germination rate and vigorous early growth under salty soils is preferred. Seed priming is a way to increase salt tolerance of plants. An experiment was conducted to investigate the effect of seed priming on germination of milk thistle under salinity condition. The treatments were 4 levels of seed priming (no priming, distilled water as hydro priming and 0.5 and 1.0 mM salicylic acid) and 5 levels of salinity (0, 40 and 80 mM NaCl and 40 and 80 mM CaCl2). The experiment arranged as a factorial in a completely randomized design (CRD) with three replications. Results showed that salinity decreased germination percentage and germination rate to about 16 and 32% in 80 mM CaCl2 level compared to control, respectively. The highest mean germination time (5.7 day) were belonged to 80 mM CaCl2. Radicle and plumule length significantly decreased by 80 mM NaCl and 40 and 80 mM CaCl2. The lowest seedling weight and seed stamina observed in 80 mM CaCl2. 0.5 mM salicylic acid improved all traits except mean germination time as compared to control.  Salicylic acid (0.5 mM) improved radicle length under 0, 40 and 80 mM NaCl salinity levels as well as increased plumule length at the 0 and 40 mM NaCl salinity conditions.