Jafar Biabani; Abdolrahman Mohammadkhani; masoud fattahi
Abstract
Objective: 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 ...
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Objective: 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.
Methods: 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.
Results: 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.
Conclusion: 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.
Ali Shayanfar; Farshid Ghaderifar; Rahmatollah Behmaram; Afshin Soltani; Hamidreza Sadeghipour
Abstract
Secondary seed dormancy is known as the major reason for seed persistence of canola (Brassica napusL). Volunteer’s rapeseeds emerging from the soil seed bank can lead to unwanted gene dispersal to other plants after breaking secondary seed dormancy. At the current study, secondary dormancy was ...
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Secondary seed dormancy is known as the major reason for seed persistence of canola (Brassica napusL). Volunteer’s rapeseeds emerging from the soil seed bank can lead to unwanted gene dispersal to other plants after breaking secondary seed dormancy. At the current study, secondary dormancy was induced in 41 lines and 5 cultivars of canola under laboratory condition with using polyethylene glycol 6000, during 14 days and secondary seed dormancy recorded. This study was conducted as a randomized complete design. High germination percentage was observed at the all lines and cultivars (higher than 94%), and they were classified at five groups included very low, low, medium, high and very high secondary dormancy using cluster analysis. Among different lines, five genotypes were included at the very low group and two genotypes were included at the very high group. The other lines were placed in average and low groups. It was observed that five varieties (RGS003, Zarfam, Hyola401, Hyola308 and Hyola50) had average secondary dormancy (40-60%) that was related to breeding ignorance about secondary dormancy during seed production process. Lines classification based on different levels of secondary dormancy helps seed producers to select lines with low levels of secondary dormancy along with high yield and other characteristics, in order to deal with problems in seed producing process.
Yalda Ghazi-Vakili; Ali Reza Motallebi-azar; Fariborz Zare Nahandi; Naser Mahna
Abstract
Due to the importance of production and propagation of virus-free potato plants, some of the factors involved in the propagation of potato (plantlet production and virus-free in vitro microtuberization) has been studied. In most reports, adding a mixture of amino acids play an important role in plant ...
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Due to the importance of production and propagation of virus-free potato plants, some of the factors involved in the propagation of potato (plantlet production and virus-free in vitro microtuberization) has been studied. In most reports, adding a mixture of amino acids play an important role in plant tissue culture and development of the explants in many cases increase. This experiment was conducted in a completely randomized design with three replications to investigate the effects of glutamine, arginine, asparagine, cysteine and their combinations on microtuberization of potatoes. Lateral buds from in vitro shoots were cultured on MS medium under sterile conditions. Cultures were kept in constant darkness and temperatures of 17 ± 2°C in a germinator. During the first month of culture microtuberization rate and after two months other microtuberization traits such as microtubers weight was measured. Analysis of variance showed that all traits except microtuber without rest were significantly affected by four amino acids. In this study, arginine in combination with asparagine had a positive role in improving the most important characteristics such as weight and microtuberization rate.