SEED AND PLANT PRODUCTION JOURNAL
Year:2018 | Volume:34-2 | Issue:2|Papers Count:7

To study the effect of cytokinin (0 as control and 50 mgl-1) and auxin (0 as control and 10 mgl-1) hormones and planting arrangements (single row, double rows and furrow plantings) on grain yield and yield compoments of maize SC704 under saline stress conditions, a field experiment was conducted as split factorial arrangements using randomized complete block design with three replications in 2013 and 2014 in Bushehr Agricultural and Natural Resources Research Center. The experimental factors included: planting arrangement in main-plots and growth regulators as factorial in subplots. Results showed that double rows and furrow planting increased grain yield by 31. 7% and 74. 6%, respectively (P<0. 01). Foliar application of cytokinin and auxin in both years increased grain yield. The highest plant height obtained in furrow planting and foliar application cytokinin hormone. Cytokinin and auxin application increased the number of rows per ear and number of grain per row in all planting arrangements. Cytokinin and auxin increased 1000 grain weight by 14. 42% and 14. 46%, respectively (P<0. 01). The application of cytokinin and auxin in different planting arrangements increased harvest index by 19% and 30. 72%, respectively (P<0. 01). The results showed that furrow planting and foliar application of cytokinin in the V8-V10 stage and auxin at the silking stage increased grain yield of maize SC704 under saline stress conditions.

This study was performed to investigate the effect of plantlet age and different biological fertilizer on mini-tuber production of three potato cultivars in aeroponic system for achieving the highest mini-tuber number and weight, in Ardabil Agricultural and Natural Resources Research Station. In the first year (2014), 200 plantlets of three commercial potato cultivars; Agria, Caesar and Banba were propagated by single node cutting method, in the laboratory. In the second year (2015), plantlets were planted in a factorial experiment based on completely randomized design with three replications and three factors, in the greenhouse. The first factor included three plantlet ages (30, 40 and 50 days), the second factor was three potato commercial cultivars (Agria, Caesar and Banba) and the third factor was three different biological fertilizers [control, Biofarm and three bacteria combination (Enterobacter cloasse strain Swri1, Azosprillum lipoferum strain of and Sedomonus putida strain 169)]. Analysis of variance showed that the effects of plantlet age and plantlet age × biological fertilizer intraction on lateral stem number per plant, cultivars and cultivars × biological fertilizer intraction on mini-tuber number and weight per plant were significant. The effect of biological fertilizer was significant on mini-tuber number and weight per plant, average mini-tuber weight, plant height and lateral stem number per plant. The application of combination of three bacteria in Banba potato cultivar increased mini-tuber number and weight per plant. The mini-tuber number and weight per plant were 119. 8 mini-tubers with 862. 9 gram per plant in combination of three bacteria. It was concluded that for increasing the mini-tuber number and weight per plant in potato cultivars, application of combination of three bacteria (Enterobacter cloasse strain swri1, Azosprillum lipoferum strain of and Sedomonus putida strain 169) is recommended.

Pear rootstock Pyrodwarf as semi-dwarfing rootstock has been used because of its many advantages. To optimize in vitro propagation conditions and study the effect of basal medium, different combinations of plant growth regulators on micro propagation and rooting of Pyrodwarf rootstock, this study was conducted. In the first experiment, the effect of five basal media including: MS, 1. 5MS, 2MS, WPM and B5 were studied on shootlet number and shootlet length. In the second experiment, the effect of two plant growth regulators; BAP and TDZ with four concentrations (0, 0. 5, 1 and 2 mgl-1) was studied on shootlet number, shootlet length, node number, internode number and internode length. In the third experiment, the effect of two basal media MS and ½ MS supplemented with two plant growth regulators: IBA and NAA with four concentrations (0, 1. 5, 3 and 4. 5 mgl-1) was studied under three and four days darkness for root induction. Acclimatization of rootstock was surveyed separately in coarse perlite, fine perlite, peat moss and perlite + peat moss. Results showed that the highest proliferation, 3. 71 shoots per explants, was observed in B5 medium. The highest shoot number with mean of 12. 44 shoots per explant were observed in concentration of 1 mgl-1 BAP. The highest rooting percentage with mean of 100% and root number with mean of 3. 04 was observed in ½ MS media supplemented with 4. 5 mgl-1 IBA. The roots with better quality were observed in induction for three days in darkness. The highest acclimatization and survival percentage of seedlings in pyrodwarf rootstock obtained in coarse perlite growth medium.

In recent years, grape growing areas has extended to warm region, therefore, study on grapevine response to heat stress for screening and selection of heat tolerant cultivars is important. Antioxidant systems activity in plants is one of the most important plant adaptation mechanisms to abiotic stresses. This research aimed to determine the response of antioxidant enzymes such as catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and superoxide dismutase (SOD) activities to heat stress in six grapevine cultivars under vineyard conditions. Some physiological traits including; total leaf chlorophyll, chlorophyll a and b contents and chlorophyll fluorescence (Fv/Fm) response were also measured. Results showed that CAT and POD enzymes played criticals roles in the grapevine defense system under high temperature stress. Flame Seedless and Rotabi cultivars had high CAT and POD enzymes activities. Total chlorophyll, chlorophyll a and b concentration were associated to higher Fv/Fm, and were the highest in Flame Seedless followed by Rotabi cultivar. It was concluded that the highest levels of physiological parameters and antioxidant enzymes activities involved in heat stress tolerance in Flame Seedless and Rotabi cultivars, respectively. Similarity between results of this research and previous study under heat stress conditions in which Flame Seedless and Rotabi cultivars had the highest yield showed that physiological traits and antioxidant enzymes activity have the potential for screening grapevine cultivars for heat stress tolerance.

In recent years some of pear nurseries have been suggested using vegetative propagated European pear (Pyrus communis L. ) `Pyrodwarf’ rootstock for pear orchards in Iran. This research was carried out to explore the scion/rootstock interaction, root growth and root length and distribution of two Asian and one European pear cultivars on vegetatively propagated “ Pyrodwarf” rootstock. Two Asian pear; cv. `KS6ˊ and cv. `KS10ˊ with one European pear; `Shahmiveh’ cultivar, budded on `Pyrodawrf' rootstock in late August 2012. The scion’ s vegetative and rootstock root growth and distribution were recorded under Tehran environmental conditions in 2014 and 2015 growing seasons. In addition, to study the scion/rootstock compatibility, the amount of starch in the above and below of the graft union was determined using isozyme study by polyacrylamide gel electrophoresis. The results showed that the vegetative growth of cultivars on “ Pyrodwarf” rootstock was significantly different. The growth of `KS10ˊ cultivar was lower than `KS6ˊ and `Shahmivehˊ cultivars. Starch content was significantly different among the cultivars. `Shahmiveh’ had the lower starch content than the other two cultivars. Isozymes study showed A and B bands in the `Pyrodwarf' rootstock and `Shahmiveh’ cultivar, however, only B band was observed in the `KS6ˊ and `KS10ˊ cultivars. `Shahmiveh’ as an European pear cultivar showed good compatibility on `Pyrodwarf' rootstock, but `KS6ˊ and `KS10ˊ as Asian pear cultivars showed semi-incompatibility on `Pyrodwarf'. The evaluation of the `Pyrodwarf' root system in comparison with `Dargazy’ seedling rootstock showed that the main roots of this rootstock grew horizontally near to the top layer of the soil. Roots did not penetrate and grew well in the deeper layers of the soil. It was conclude that due to the root system and structure, `Pyrodwarf' rootstock may not be suitable for the arid and semi-arid areas and should not be recommended to pear fruit orchards which facing shortage of irrigation water. Further research using suitable and compatible rootstocks with optimum root growth under drought conditions would warrant suitable fruit production of Asian and European pear orchards in Iran.

To evaluate the effect of delayed planting and irrigation regimes on yield, yield components and some agronomic traits of winter rapeseed varieties, two separate field experiments (I: optimum irrigation and II: terminal drought) carried out as split plot arrangements in randomized complete block design with three replications in 2014-2016 cropping seasons at Zarghan field station, Agricultural and Natural Resources Research and Education Center of Fars, Iran. In each experiment three planting dates (07, 17 and 27 October) and four winter rapeseed varieties; two open pollinated cultivars (Talayeh and Okapi) and two hybrids (Neptune and Elvis)) were assigned to main plot and randomized in subplot, respectively. The results indicated significant effect of irrigation and variety on all traits. The effect of planting date was significant on all traits except 1000 seed weight and number of seed per pod. Terminal drought decreased plant height, days to maturity, seed yield and yield components. The decrease in seed yield by terminal drought and delayed planting was 23. 9 and 18. 4%, respectively. The reduction of 17. 2% of seed no. per pod by terminal drought stress and 16. 2% of pods per plant by delayed planting caused yield reduction. The results also showed that the effect of terminal drought stress on seed yield and harvest index was much higher than the delay in planting. Tallayeh which maintained seed yield superiority under different conditions can be recommended as the suitable variety for similar growing conditions.

Fruit production with good quality depends on determination of self-fertility and self-incompatibility of cultivars as well as the best pollinizer. Therefore, this research was carried out to study the best pollinizer for introduced quince cultivar “ Viduja” . The effects of the male parents, including KVD2, KVD4, Isfahan, Torsh and also open pollination were studied on quantitative and quality characteristics of the pollen recipient parent in a randomized complete block design with four replications at the Horticultural Research Station of Mobarakeh, Isfahan, Iran. To determine the best pollinizar, shoots of the donor parents were cut and the required amount of the pollen grains was prepared in the laboratory. Flowers of “ Viduja” cultivar were emasculated in the balloon stage and covered with isolation bags. The isolation bags were removed temporarily and emasculated flowers were crossed with the pollen of donor parents. Female parent incompatibility was evaluated with covering a number of flowers in the balloon stage. Hand self-pollination and open pollination were carried out for “ Viduja” cultivar. The results showed that there was not fruit set in self-pollinationed treatments. The highest fruit set obtained with pollens of KVD2 genotype. The length, diameter and fruit weight were not affected by the type of pollen, and only natural and hand self pollinated treatments had significant differences with other treatments. The highest total soluble solids were obtained from pollinated flowers with pollens of KVD2 genotype and open pollination. The pollen grain type had no significant effect on other fruit quality traits. In conclusion, the best source of pollen for “ Viduja" quince cultivar was KVD2 genotype. Therefor the cultivation of this genotype is recommended in the “ Viduja” orchards.