IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2003 | Volume:3 | Issue:3-4|Papers Count:11

This research was carried out to study the seed production of different genotypes of onion, effect of bulb size, correlation between traits and their role in increasing seed yield. A split plot experiment with 13 selected genotypes (main plot) and three sizes of mother bulb (sub plot) were used in a randomized complete block design with three replications in 1999 at the Research Station of the College of Agriculture. Isfahan University of Technology. Results showed significant (P=0.01) differences among genotypes for all measured traits related to seed yield. Large differences for most traits indicated high genetic variability among 13 genotypes examined. Inflorescence emergence, flowering and seed ripening occurred earlier in 'Tarom' while in 'Ghom', 'Abarkooh' and 'Yellow Sweet Spanish' observed later. Highest number of inflorescences and seed yield plant-1 produced in 'Ghom', whereas' Azarshahr', 'Dorcheh' and 'Yellow Sweet Spanish' produced lower amounts of seed. Bulb size showed significant effects on measured traits so that with increase in bulb size, number of inflorescences plant-1, height of inflorescence and bulb yield plant-1 were increased. A positive correlation was observed between seed yield plant-1 and days to inflorescence emergence and also number of inflorescences plant-1. Using eight traits, based on Pseudo Hotelling's T2 test and cluster analysis, the genotypes were classified in three groups.

Recently the effect of ethylene on induction of physiological and morphological stress responses of iron deficiency, especially on strategy I plants, has been investigated. Also the role of these responses on iron and other cation uptake by plant roots and on the influence of nutrient deficiency on these responses was experimented. The importance of ethylene effect as a plant hormone on cation uptake mechanism caused that we study its influential effects on micronutrients uptake in citrus. Therefore, Mexican sourlime (Citrus aurantifolia Swing) seedling roots were treated by ethephon and root morphological changes, the concentration of Fe, Mn, Zn and Cu in roots and leaves were studied. The results showed that ethylene induced root growth by high axillary root production and also enhanced root hair formation and subapical root swelling. Moreover, ethylene increased micronutrient uptake, specially Fe and Mn by roots. The indirect effect of ethylene through induction of root growth on leaf area expantion reduced specific leaf weight (SLW) and conduced dilution effect in leaves. Under this condition, calculation of leaf micronutrient concentration based on the dry weight, gave little information about them in comparison with control, while the content of this elements per leaf presented better commentry about them. This index showed that the amounts of Fe, Mn, Zn and Cu enhanced in leaves. Local effects of ethephon on Fe and Mn uptake by roots indicated that physiological responses had higher efficiency than morphological changes in respect of Zn and Cu that were mostly affected by roots growth. Thus, ethylene have effective role on Mexican lime roots micronutrient uptake via physiological or morphological changes.

Genetic variation of 12 natural populations of wild almonds (Amygdalus spp.) growing in Esfahan province was assessed using RAPDs (random amplified polymorphic DNA) Markers. Genomic DNA extracted from young leaf tissues, and amplification reactions carried out using nine selected 10-mer primers. The resulting band sizes varied from 200 to 3229 bp. Jaccard's similarity coefficients and the unweighted pair-group method (UPGMA) were used to produce the cluster diagram. Based on this method, the populations fell into four groups that each belongs to one of the four almond species included A. scoparia, A. haussknechtii, A. lycioides, and A. elaegnifolia. Overal, a relatively high degree of diversity was detected both within and between populations. According to the mean of intraspecific similarity coefficients, the genetic variation in A. haussknechtii was greater than the other species. Also, regarding to the interspecific variation, the greatest genetic distance was between A. lycioides and A. haussknechtii. Therefore, regarding to the relatively high and more exact diversity demonstrated among these plants, it can be utilized in breeding of valuable and important traits and thus it can provide the possibility of considering useful genes in new individuals.

A population of offspring from crosses between 'Bidane Qermez' and 'Muscat Hamburg' grape cultivars was used to investigate the inheritance of alleles at SSRs loci in controlled pollinated offspring. DNA was extracted from 46 seedlings as well as corresponding parents. Amplification of DNA was carried out using different colored fluorescent primers at 6 SSRs loci (VVS2, VVMD5, VVMD32, VVMD36, ssrZAG47 and ssrZAG79) in which the parents were completely polymorphic. Allele sizing was determined using ABI Prism 3100 DNA analyzer with Capillary Electrophoresis System at central laboratory of the Center for Gene Research at Oregon State University, U.S.A. Results showed that 94% of the seedlings shared one allele at each locus with parents indicating their hybrid nature, while 6% of the progenies with having only the female parent alleles were the result of self-pollination. Allele's distribution among the progenies determined their codominant inheritance. No significant differences (P>0.07) with Mendelian codominant ratio (1: 1: 1: 1) were observed using χ2 test. Three off springs resulted from self-pollination showed only the presence of maternal alleles either as homozygous or heterozygous. These results show the importance and potential of microsatellite loci in detecting parents-progeny relationship prior to study for inheritance of characters and alleles, bulked segregation analysis, gene and linkage maps and historical reconstruction of fruit trees pedigree.

Experiments were conducted at Estahban Research Station to evaluate the effects of plant growth regulators on hastening maturity, in order to escape damage by early rain during harvesting season. To stimulate growth and maturation of fig fruit, ethephon (125, 250, 500, 625 and 750 mg 1-1) and 2, 4-dichlorophenoxyacetic acid (5, 10, 15, 20 and 25 mg 1-1) and 2, 4, 5-trichlorophenoxyacetic acid (10, 20 and 30 mg 1-1) were applied to the leaves and fruits on July 6, 13 and 20 in two successive years of 1996-1997. The results of these studies showed that, growth regulators when applied on July 20 reduced fruit removal force (FRF), however, when applied on July 13 decreased average fruit weight. Ethephon at 500 mg 1-1, 2, 4-D at 20 mg 1-1 and 2, 4, 5- T at 20 mg 1-1 reduced total length of harvesting period. 2, 4-D at 5 mg 1-1 had better effect on increasing fruit diameter than other treatments. Growth regulator treatments had no adverse effects on leaf shape and/or fruit quality.

'Shahmiveh' pear is one of the most important pear cultivars grown extensively in Iran. During 2 years (2000 and 2002), flowers of 'Shahmiveh' pear were self- and cross-pollinated with pollen grains of pear cultivars: 'Bartlett', 'BeurreBosc', 'BeurreHardy', 'Koshia', 'Luisbon', 'Peighambari' and' Sefasleh'. 'Shahmiveh' pear showed gametophytic self-incompatibility. therefore use of compatible pollinizer for 'Shahmiveh' is necessary. Pollen grains of 'Koshia' and 'Bartlett' induced highest fruit set, therefore they are suitable pollinizers for' Shahmiveh'. 'Peighambari' pollen grains had the lowest rate of germination and could not fertilize 'Shahmiveh' flowers. Therefore, it can not be recommended as pollinizer for this cultivar. It was found that pollinizer can influence fruit set and seed number per fruit. Pollen grain source had no significant effect on fruit weight and TSS. There was no correlation between seed number per fruit and fruit weight.

In order to evaluate the rooting ability of semi-hardwood cuttings of some olive (Olea europaea L.) cultivars under mist condition, an experiment was conducted in two years (1999 and 2000) at the Tarom Olive Research Station in Zanjan Agricultural Research Center. A completely randomized design (CRD) with three replications and 21 cultivars were used. Analysis of variance showed significant differences among cultivars for rooting percentage and number of roots per cutting. Date of the cutting affected rooting ability. 'Mahzam- Abousatl', 'Mosabi', 'Balady' and 'Kavi' cultivars were easy-to-root cultivars with 88.5, 86.0, 80.8 and 79.3 rooting percentage, respectively. 'Kalamata' and 'Dane' cultivars had the least rooting percentage with 34.67 and 42.33%, respectively. 'Balady', 'Mission', 'Mahzam- Abousatl'. 'Cipressino'. 'Fuji' and 'Manzanillo' were better than other cultivars with 16.8, 16.1, 15.3, 15.14 and 13.3 mean number of roots per cutting, respectively. 'Dane', 'Kalamata', 'Mastoidis', 'Mari-e-Gorgan' and 'Konservolia' had the least rooting ability with 5.7, 7.1, 7.2, 7.2 and 7.5 mean roots number per cutting, respectively.

Bunch thinning is considered as an important cultural operation for improving the quality of date fruits as well as creating a balance between photosynthesis and carbohydrate production and the fruit quantity. Quality of dates is improved by increasing fruit weight and size. This experiment was carried out in Shadegan (Khuzestan province) using a completely randomized block design with five treatments in three replicates for two years. The treatments were: leaf/bunch ratios of 8-9: 1, 10-11: 1, 12-13: 1, 14-15: 1 and natural ratio (control). Results showed that the leaf/bunch ratio had a significant effect on fruit length and yield but it did not have a significant effect on fruit diameter and weight. Based on this research, the leaf/bunch ratio of 8-9: 1 can be recommended as the best bunch thinning treatment for' Sayer' date.