Journal of Plant Physiology and Breeding
Volume:1 Issue: 2, Summer-Autumn 2011

Salinity is one of the major abiotic challenges influencing plant productivity worldwide. To examine the response of two alfalfa cultivars (Bami and Hamedani) to six levels of water salinity (0, 25, 50, 75, 100, 125 mM L-1 NaCl), a glasshouse experiment was conducted at the College of Agriculture, Shiraz University, Shiraz, Iran in 2008. The results showed that in Bami (which appeared to be more tolerant to salinity), with increasing salt stress from 7 to 125 mM L-1, dry weight per pot was significantly decreased from 15.1 to 10.3 g, while in Hamedani decrease in dry weight was started from 50 mM L-1 salinity level. In both Bami and Hamedani cultivars leaf area per pot was significantly decreased when salt stress was higher than 75 mM L-1. There was a significant difference in leaf relative water content (RWC) between the two alfalfa cultivars in 75, 100 and 125 mM L-1 NaCl salinity levels. With increase in salinity level, the Na+ concentration was increased from 220 to 565 mmol kg-1 dry weight in Bami, and from 238 to 643 mmol kg-1 dry weight in Hamedani. The Cl- concentration in Hamedani (622 mmol kg-1 dry weight in 125 mM L-1 NaCl) was higher than that in Bami (503 mmol kg-1 dry weight in 125 mM L-1 NaCl). The K+ concentration was increased from 203 to 604 mmol kg-1 dry weight in Bami, and from 135 to 571 mmol kg-1 dry weight in Hamedani. Furthermore, phytomass production in Bami was significantly correlated with K+ (r=0.97), and Ca2+ (r=0.96) concentrations, as well as with leaf area (r=0.50) and plant height (r=0.87). Path analysis showed that there were significant direct effects of leaf area (p=0.73), Ca2+ (p=1.02) and K+ (p=0.59) on dry weight in Bami. In Hamedani, there were significant direct effects of K+ (p=0.61) and Ca2+ (p=1.07 on dry weight. Overall, based on both correlation and path analyses, it was concluded that measurements of K+ and Ca2+ concentrations may be appropriate criteria for evaluating susceptibility of cultivars to salt stress. These results may also be used for screening the salt resistant cultivars of alfalfa.

Laser is one of the sources that induce a biological effect in higher plants. The positive effect of laser on some crops has been proved. This research was carried out to study the effect of laser radiation on the accumulation of proline in spring wheat (Triticum aestivum cv. Kavir) under different NaCl treatment levels. Semi-coherent red beam, infrared beam and one-second harmonics of Neodymium-Yttrium-Alminum Garnet (Nd:YAG) laser were chosen as illumination sources. Irradiation on seeds was conducted for 12 minutes once or twice and non-irradiated seeds were used as the control. Experiment was conducted as factorial based on completely randomized design with three replications. The results revealed proline accumulation in leaves after laser treatment and subsequently salt stress tolerance enhanced significantly. Each dosage of radiation imposed a different effect on proline content. The highest proline accumulation was observed in one-time exposure of Nd:YAG laser radiation. This is the first investigation report on using different types of lasers and their effect on proline content in the spring wheat. Results show the powerful effect of laser treatment on the improvement of wheat tolerance to salinity stress.

In order to evaluate the effects of foliar application of micronutrients (iron and zinc) and different harvesting times during seed filling on yield and mucilage percentage of psyllium (Plantago psyllium), a field experiment was carried out in 2009 at the Research Farm of the Faculty of Agriculture, University of Tabriz, Tabriz, Iran. The experiment was arranged as split plot based on randomized complete block design with four replications. The treatments were foliar application of Fe, Zn and Fe+Zn (using ferrous sulphate and zinc sulphate at the concentration of 0.35% for the both micronutrients) with the control and four harvesting times during seed filling. The results showed that seed yield, seed swelling and mucilage percentage were increased by foliar application of Fe and Zn, compared with control (untreated). The highest seed yield (832.5 kg.ha-1), seed swelling (12.78 ml) and mucilage percentage (8.35%) were recorded for spray treatment by about 31.04, 21.71 and 41.52 % improvements in comparison with control, respectively. Different harvesting times had significant effect on seed yield, seed swelling and mucilage percentage. The highest seed yield was obtained at seed maturity stage. At this stage seed swelling and mucilage percentage were the lowest, but this was overcome by large improvement in seed yield. It seems that foliar application of iron and zinc can considerably improve seed yield, seed swelling and mucilage content of psyllium.

The effect of postharvest UV-C irradiation on phenolic compounds accumulation was investigated in berries of ‘Rishbaba’ table grape (Vitis vinifera cv. Rishbaba). Grape clusters were harvested at mature stage and irradiated with UV-C using fluorescent germicidal lamp (30 W, 90 cm) with a peak emission at 254 nm for 0 (control), 5 and 10 min. UV-C treatment had significant effect on individual phenolic compounds. Catechin, epicatechin, procyanidin B2, quercetin 3-galactoside, quercetin 3-rhamnoside, chlorogenic acid and total polyphenols increased with UV-C dosage, but procyanidin B1 and cyanidin 3-galactoside decreased. Positive correlation was observed between UV-C treatment and individual phenolics except procyanidin B1 and cyanidin 3-galactoside. In conclusion, UV-C irradiation increased phenolic compounds of ‘Rishbaba’ table grape and its nutritional value.

Analysis of genetic diversity and population structure in medicinal plants is essential step in their conservation, utilization and breeding. In the present study, seven primers designed based on long terminal repeats (LTRs) of barley retrotransposons and their combinations were used to amplify DNA fragments from 12 Iranian ecotypes as well as two populations from Germany and Japan based on inter-retrotransposon amplified polymorphism (IRAP) technique. A set of eight most polymorphic primers out of 28 possible single and primer combinations yielded 456 reproducible informative data points, with 95% polymorphism.The mean of Nei’s genetic diversity index and Shannon diversity index were 0.10 and 0.16, respectively. Polymorphism information content (PIC) ranged from 0.22 to 0.32 with an average of 0.27 and marker index (MI) varied in the range of 10.10-29.30 with an average of 14.39. Analysis of molecular variance revealed higher within population molecular variation (76.30%) compared with among populations variation (23.70%). The highest and lowest genetic heterogeneity were observed in Hamedan-2 and Qazvin-1 populations, respectively. The studied genotypes were assigned into five groups based on IRAP data using Neighbor- Joining algorithm and p-distance evolutionary distance coefficient. Populations relationships were resolved using Neighbor-Joining algorithm and Nei’s genetic distance and the populations were grouped into three clusters. Our results suggest that retrotransposon based markers such as IRAP are efficient and reliable markers in determining level of genetic diversity and population structure in lemon balm.

Allium hirtifolium is endemic to Iran and grows as a wild species in the Zagross Mountains. This plant is edible and has important medicinal properties; however, there is little information about it. In the present study, A. hirtifolium was studied cytogenetically through both a routine and a differential staining (C-banding) method. The results indicated that A. hirtifolium is a diploid (2n=2x=16) species with predominantly metacentric chromosomes and a symmetric karyotype. Each of two chromosome pairs, VI and VIII, contained a secondary constriction and a small satellite. A. hirtifolium had little heterochromatin in their chromosomes. Unlike most other Allium species, there was no telomeric C-positive band.

The choice of selection and breeding procedures for genetic improvement of maize or any other crop largely depends on the type and relative amount of genetic components and presence of non-allelic interaction. In this study six generations (P1, P2, F1, F2, BC1 and BC2) from two crosses of corn, KE72012(P1) × K1263/1(P2) and B73(P1) × MO17(P2) were evaluated for several agronomic traits including yield and its components at Torough Agricultural Station of Khorasan Razavi Agriculture and Natural Resources Research Center, Mashhad, Iran, in the 2010 growing season. The experiment was carried out as a randomized complete block design with three replications. The results showed significant differences among generations for all traits in both crosses. Most of the additive, dominance, additive × additive, additive × dominance and dominance × dominance effects were significant indicating the importance of the additive, dominance and epistatic modes of gene action in controlling the agronomic characters in maize. However, dominance variance was more important than additive variance for most of the traits such as ear length, kernel number per row, kernel number per ear and grain yield, which justifies the production of hybrid varieties in maize. Broad sense heritabilities of traits were 0.29-0.87 and 0.42-0.87 for KE72012 × K1263/1 and B73 × MO17 crosses, respectively. The estimated number of genes for grain yield in the late maturing hybrid, KS 704 (B73 × MO17), was around 10, while in the early maturing hybrid, KSC400 (KE72012 × K1263/1), it ranged from 3 to 5.

A precise and accurate identification of barley (Hordeum vulgare L.) varieties for feed, malting and resistance to biotic and abiotic stresses are dependent on their genetic structure. In this study, identification and differentiation of 34 barley varieties were studied using 14 SSR markers. The results showed that a total of 77 SSR polymorphic bands were observed over all genotypes. Polymorphic alleles ranged from 3 to 9 among the markers. The markers related to 1H linkage group, represented the highest (16 alleles) and markers linked to the 7H linkage group the lowest (6 alleles) number of polymorphic alleles. The highest and lowest PIC scores estimated 0.84 to 0.39 for Bmac0316 and Bmag0136 markers, respectively. A relatively high degree of genetic diversity was appeared among the examined varieties. Primer Bmac0316 displayed the highest (0.88) and EBmac097 the lowest (0.49) distinction power (D). The highest value of average of gene diversity (alleles) was observed in Rudasht and CB79-10 varieties indicating maximum heterozygosity. Cluster analysis of 34 genotypes on the basis of data generated by 14 SSRs could differentiate all genotypes in three distinct groups. A combination of four effective SSR loci could also provide the same pattern of genotypic variability as detected by all 14 markers. Microsatellite markers could be used as complementary tools to morphological and physiological characteristics for the identification and clarification of barley varieties.