A lfalfa, a perennial forage crop, experiences seasonal changes in growth patterns and morphology in the temperate regions of the world. Fall dormancy, referring to the characteristic growth reduction and decumbent shoot orientation of certain genotypes in autumn, typically occurs in late summer and early autumn as temperature declines and photoperiod shortens (Castonguay et al., 2006;McKenzie et al., 1988). For practical purposes, the dormancy level of alfalfa cultivars is ABSTRACT Alfalfa (Medicago sativa L.) is a widely planted perennial forage crop. Fall dormancy is generally negatively correlated with winter injury in alfalfa. To understand the genetic basis of the two traits, we identified quantitative trait loci (QTL) controlling autumn growth and winter injury using a tetraploid alfalfa F 1 population. In total, 601 marker alleles were scored from 78 restriction fragment length polymorphism (rFLp), 123 simple-sequence repeat (SSr), and 48 single nucleotide polymorphism (SNp) markers. Linkage maps were constructed for each parent separately. Both maps contained eight linkage groups (LGs), with a length of 898 cM for WISFAL-6 and 845 cM for ABI408. Using interval mapping, we identified 15 QTL from an across-environment analysis and 71 QTL within individual environments for autumn plant height; winter injury; and autumn shoot, crown, and root biomass across four Iowa environments. of the 71 QTL, 42 were identified at 18 chromosomal locations that were identified in multiple environments for the same trait. possible pleiotropic QTL that contributed to dry weight of shoot, crown, and taproot were found, which partially explained the observed genetic correlations between those traits. However, few QTL were related to both autumn plant height and winter injury, supporting the observation of no genetic correlation between the two traits in this study. These results indicated that the two traits could be manipulated independently and, possibly, efficiently improved using marker-assisted selection. Because most QTL identified in this study were mapped to intervals of at least 10 cM, validation and localization in additional populations is needed to facilitate application of marker-assisted selection.

A field experiment was conducted at University of Agriculture, Faisalabad, Pakistan, to investigate the effect of foliar application of silicon on yield and quality of fine rice (Oryza sativa L.). The research was designed as randomized complete block design (RCBD) having three replications and 6m x 4.5m net plot size was maintained. Foliar applications of silicon’s aqueous solution were used as treatments comprised of control, 0.25%, 0.50%, 1.00% silicon solutions. Nursery of 30 days old seedling nursery was transplanted to the plots under aerobic condition and 22.5cm hill to hill distance was maintained. Sodium silicate (20.35% Si) as the source of silicon (soluble in warm water) was used. Fertilizer inputs as nitrogen, phosphorus and potassium were uniformly applied at the rate of 100, 67, 67 kg ha-1 while all other agronomic practices were kept constant for all the treatments. The data from the field (yield components) as well as lab analysis (quality parameters) was recorded according to the standard procedures. Fisher’s analysis of the variance technique was used for statistical analysis and treatment’s mean differences were compared using least significant difference (LSD) test at 5% probability level. Silicon showed no significant effect on plant height, harvest index, number of kernels and opaque kernels percentage. Silicon (0.50% silicon solution) produced maximum grain diameter and grain protein while silicon @ 1.00% silicon solution resulted maximum in number of productive tillers, straw yield, spike per panicle, 1000 grain weight, paddy yield and grain starch. All others parameters have overlapping results of different silicon levels.

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Reed canarygrass, Phalaris arundinacea L., produces high biomass yields in cool climates and wetlands. The number and timing of harvests during a growing season directly affect biomass yield and biofuel quality. In order to determine optimum harvest management, seven cultivars of reed canarygrass were planted in field experiments at Ames, IA; McNay, IA; and Arlington, WI in the upper Midwestern USA and harvested once in autumn or in winter, twice in spring + autumn or spring + winter, or three times during the season as hay. Biomass yield varied considerably among harvest treatments, locations, and years, ranging up to 12.6 Mg ha −1 . Dry matter percentage ranged from 37% for spring-harvested biomass to 84% for overwintered biomass. The three harvest hay and two harvest spring + autumn managements produced the highest biomass yield compared to other systems, but the advantage, if any, of hay management was small and probably does not justify the cost of additional fieldwork. More mature biomass, such as that found in the single harvest systems, had higher fiber concentrations. Overwintered biomass had superior biofuel quality, being low in P, K, S, and Cl and high in cell wall concentration. However, winter harvest systems had lower yield than autumn harvest and in some years, no harvest was possible due to lodging from snow compaction. The main limitation of a two harvest system is the high moisture content of the late spring/early summer biomass.

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Soil salinity is a major abiotic stress which adversely affects the yield and juice quality in sugarcane. However, the mineral nutrient status of plant plays a crucial role in increasing plant tolerance to salinity. We investigated the effects of K and/or Si on plant growth, yield and juice quality in two sugarcane genotypes differing in salinity tolerance. Addition of K and Si significantly (P ≤ 0.05) increased K and Si concentrations and decreased the accumulation of Na+ in plants under salt stress. Cane yield and yield attributes were significantly (P ≤ 0.05) higher where K and Si were added. Juice quality characteristics like Brix (% soluble solids in juice), Pol (% sucrose in juice), commercial cane sugar (CCS) and sugar recovery in both sugarcane genotypes were also significantly (P ≤ 0.05) improved with the supplementation of K and Si. For most of the growth parameters, it was found that K either alone or in combination with Si was more effective to alleviate salt stress in both sugarcane genotypes than Si alone. Moreover, the beneficial effects of K and Si were more pronounced in salt sensitive genotype than in salt tolerant genotype. The results suggested that K and Si counteracted the deleterious effects of high salinity/sodicity in sugarcane by lowering the accumulation of Na+ and increase in K+ concentration with a resultant improvement in K+/Na+ ratio which is a good indicator to assess plant tolerance to salinity.

Abstract:Silicon is known to ameliorate the deleterious effects of drought on plant growth. We evaluated growth of wheat (CV. Inqlab-91) on different soil water regimes as affected by Si application. Silicon was added in soil @ 50 mg/kg and 150 mg/kg of soil. Plants were grown with three levels of soil water contents viz 50%, 75% and 100% of field capacity. Water deficiency in soil significantly reduced shoot biomass and spike weight of wheat plants. Silicon application significantly (p<0.01) increased plant biomass, plant height and spike weight at all levels of water contents. Poor growth of plants in water deficient conditions was significantly improved with Si application. Silicon application significantly increased Si concentration and uptake in wheat plants grown at all three soil water levels. Mechanisms underlying growth improvement under drought are still unclear and must be explored.Keywords: Drought, silicon, wheat. ‫ﺍﻟﻘﻤﺢ‬ ‫ﻋﻠﻰ‬ ‫ﺍﻟﺴﻴﻠﻜﻭﻥ‬ ‫ﺇﻀﺎﻓﺔ‬ ‫ﺘﺄﺜﻴﺭ‬

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