جستجوی مقالات مرتبط با کلیدواژه "جوانه گل" در نشریات گروه "زراعت"

Almonds are high in antioxidants, vitamin E, protein, and fiber. This nutrient-rich nut is an excellent addition to any diet since it is a versatile ingredient linked to several health benefits. The development of communications have led to a wider cultivation of temperate fruits, cultivars being selected and grown in different environmental conditions. This situation has increased the risks derived from the incomplete breaking of dormancy, and encouraged studies concerning the chilling and heat requirements of fruit cultivars for breaking dormancy and flowering. Estimating chilling and heat requirements of flower buds in fruit trees is important due to predicting flowering time for appropriate site selection to escape spring frost damage.

In order to investigate the chill and heat requirements of commercial almond cultivars, a factorial experiment was planned and implemented in a completely randomized design with 3 replications in Shahrekord university lab (in 2017). The first factor included commercial almond cultivars in five levels (Mamaei, Rabi, Sefid, Shahroud 7, and Shahroud 12) and the second factor included chilling in seven levels (100, 200, 300, 400, 500, 600, and 700 hours at 4-7 °C). As soon as dormancy was induced in the buds of each cultivar, 75 branches were prepared and transferred to a refrigerator with a temperature of 4 to 7 ° C to determine the chilling requirement. The samples were taken out of the refrigerator and placed in water and sucrose solution in the greenhouse environment, and the flowering status of flower buds was examined.

The results illustrated that the chill and heat requirements of Sefid and Mamaei cultivars were lower than average requirements of all cultivars in this respect. Furthermore, these two cultivars had the lower chill and heat requirements than other cultivars. Also, Sefid cultivar needed 170 hours of chill requirements and 5886 growing degree hours’ heat and Mamaei cultivar needed 170 hours of chill and 7707 growing degree hours’ heat. Rabi cultivar had lower chill and heat requirements than the average of all cultivars, but in Shahroud 7 cultivar both of chill and heat requirements were high. Shahroud 7 cultivar needed to 220.5 hours of chill and 10958 of heat growth degree hours for blooming. On the other hand, Shahroud 12 cultivar was identified as a cultivar with high chilling requirements and low heat requirements.

The minus effects of the lack of chilling for breaking dormancy in temperate fruits, both in vegetative growth, and fruit-bearing have been proved. Chilling requirements of temperate fruit cultivars have to be fully satisfied, if dormancy breaking is to result in the desired vegetative growth, and if the fruit-bearing capacity is to be fulfilled. On the other hand, in case of low chilling requirements blooming happens too early and cold temperatures produce an important loss of yield by frost.

In pistachio flower buds is formed on the lateral and terminal branches of current growth and bearing happens on one-year-old branches. To achieve higher yield, the production and selection of the best bearing shoots is important in the orchard management. The aim of this research was to explore and determine the relationship between size and type of shoot with fruit bearing in some pistachio (Pistacia vera L.) cultivars under Khorasan Razavi climatic conditions. This research was carried out using randomized complete block design with three replications in 2012 and 2014 in pistachio collection orchard at the pistachio research station of Feizabad, Khorasan Resavi province, Iran. Three pistachio cultivars including: Abbasali, Akbari and Badami-Sefid were evaluated. The results showed negative significant correlation between diameter of terminal shoot and the number of nuts on cluster of terminal branch (r = -0.67*), and between the number of flower buds on lateral shoot and the weight of flower bud on lateral shoot (r = -0.64*). There was also negative significant correlation between the percentage of blank nut and the weight of flower buds on terminal shoot (r = -0.78*), and between the number of flower bud on terminal shoots and the weight of dry nut in terms of ounce (r = -0.84**). On the other hand, there was positive significant correlation (r = 0.79*) between lateral shoot length and the number of flower bud. The effect of year on the number and length of lateral shoots, diameter of terminal shoots, abscised flower buds on lateral shoots, the weight of flower buds on the terminal and lateral shoots and the weight of nuts was significant (P < 0.01). There was not significant correlation between diameter and length of terminal shoots and the number of flower buds, but there was positive correlation between lateral shoot length and the number of flower buds. Therefore, any orchard management prectices that prevent the excess growth of terminal shoots and also increase the growth of lateral shoots will lead to increasing pistachio yield. In conclusion, the results of this research will be useful for the orchard management and suitable pistachio trees pruning for higher yield.

An experiment was conducted to evaluate efficiency of different time and duration of hot water for lettuce physical emasculation. In this research, immerse side branches of the inflorescence in the blooming and bud stages , put in hot water (40 and 50° C) where water at temperatures 25° C was used as control, for 20, 35, 50 and 65 seconds. Analysis of variance revealed that different water temperatures had significant affects on the percentage of hybrid seeds in the blooming and bud stage (two days before flowering), whereas the hot water emasculation and their interaction had no significant affects. The highest percentage of hybrid seeds (94.57%) and non-fertile pollens (84.07%) were obtained by the using of water at temperature 50° C .