نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار، مؤسسه تحقیقات ثبت و گواهی بذر و نهال، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
2 مربی، مؤسسه تحقیقات ثبت و گواهی بذر و نهال، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
3 کارشناس ارشد، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان فارس، سازمان تحقیقات، آموزش و ترویج کشاورزی، شیراز، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Considering the adverse effect of changing climate, it is necssary to introduce new commercial high-yielding and marketable almond cultivars with different chilling and heat requirements, flowering time, which can adapt to various regions. Therefore, almond trees of three recently registered cultivars named; Aria, Bardia and Zeighami and two control cultivars grafted on bitter almond seedlings were compared using randomized complete block design with five replications from 2018-21 in an almond orchard in Neyriz of Fars province in Iran. Chilling and heat requirements, tree growth vigor, yield related traits, and relationships between different pomological and morphological characteristics were measured and evaluated. The results showed that cv. Aria was superior to the other cultivars due to its higher trunk cross-sectional area (TCSA) (325 cm2) and production and yield efficiency (100.26 g nut and 25.36 g kernel per cm2 TCSA). The proportion of double kernels and kernels in the Zeighami and Bardia cultivars, respectively, was below the standard classification for almonds. Cv. Aria and cv. Bardia had the lowest chilling requirements (296 CU) and cv. Ferraduel the highest (515 CU). The heat requirement of the newly registered almond cultivars was also lower than control cultivars. Aria and Bardia cultivars flowered two weeks earlier than control cultivars. In conclusion, cv. Aria is a suitable commercial almond cultivar for being grown in regions with no of spring frost risk.
Keywords: Almond, Distinctness, Dry fruit yield, Kernel yield, Production efficiency.
Introduction
There is a need to introduce adapted temperate fruit trees to mitigate the adverse effects of climate change, especially in Iran. In addition, the improvement of genetic diversity in orchards through the identification and registration of new commercial cultivars of horticultural products is the most important platform for the protection of the germplasm of these valuable plants. Nowadays, almond breeding programs focus on the identification and introduction of high-yielding and marketable cultivars with low chilling requirements that can be adapted to regions with mild winters (Alonso Segura et al., 2005).
Understanding the relationship between quantitative pomological and morphological traits with kernel yield and production efficiency is also important in almond breeding programs. This research aimed to evaluate morphological and pomological characteristics, tree growth vigor and yield of three recently registered and two commercial almond cultivars under environmental conditions of Neyriz of Fars province in Iran.
Materials and Methods
Three recently registered cultivars named; Aria, Bardia and Zeighami and two control cultivars; Ferraduel and Ferragnese, were studied in using randomized complete block design with five replications from 2018-21 in an almond orchard in Neyriz of Fars province in Iran. The chilling requirement was calculated using the Utah model as chilling unit (CU) as well as the Positive Utah model as positive chilling unit (PCU). Heat requirement was calculated as growing degree hours (GDH).
Tree growth vigor at the end of the growing season was evaluated by measuring the circumference of the trunk at a height of 20 cm above the graft. The trunk cross-sectional area (TCSA) was calculated as an estimate of the tree growth vigor. Production efficiency (PE) was estimated as in-shell almond production normalized to TCSA. Yield efficiency (YE) was calculated as kernel production per tree normalized to TCSA. Kernel yield is the proportion of kernels by weight of the total nut.
The cultivars were evaluated based on 46 morphological and pomological characteristics included in the UPOV Guidelines for the Distinctness, Uniformity and Stability (DUS) tests for Almond (Anonymous, 2019). The expression of quantitative characteristics were evaluated based on determined ranges (Giordani et al., 2016). The most important traits for grouping of the cultivars were identified using principal component analysis.
Results and Discussion
The results of this research showed the superiority of the recently registered almond cv. Aria as compared to check cultivars; Ferragnese and Ferraduel and two other newly registered cultivars; Bardia and Zeighami considering tree growth vigor (TV), production efficiency (PE), yield efficiency (YE) and kernel yield (KY) in the Neyriz region. Although the kernel weight (KW), yield and production efficiency of cv. Zeighami were high, double kernel (%) of over 60% was undesirable traits of this cultivar. The recently registered cv. Bardia also had kernel yield of less than 25%. The flowering time of the recently registered cultivars was about two weeks earlier than that of the check cultivars, although none of the studied almond cultivars suffered frost damage during flowering in 2018-21. Among almond cultivars with the highest (cv. Ferraduel) and the lowest cold requirement (cv. Aria), there was 15 days difference in the estimation of chill accumulation. The highest heat requirement was found for cv. Ferragnese and the lowest for cv. Aria and cv. Bardia. Based on the all studied traits, cv. Aria can be considered as suitable commercial almond cultivar for being grown in areas where there is no risk of spring frost (Alonso Segura et al., 2005). Principal component analysis of pomological, morphological traits and yield related traits resulted in four principal components, with only two principal components PC1 and PC2 accounting for 70% of the total observed variance. The most important traits of almond cultivars were; harvest time, resistance to nut cracking, foliage density, the degree of undulation of petal margins, the intensity of the brown color of the kernel, the time of beginning of flowering, the tree growth vigor, the length and width of the leaf blade, flower diameter, stone endocarp thickness, the tree growth habit, the degree of fruit pubescence, yield efficiency and production efficiency. Almond cultivars were classified in four groups using all traits on the two-dimensional diagram of two main components. In conclusion, cv. Aria is a suitable commercial almond cultivar for being grown in regions with no spring frost risk. The results of this research can be used for establishment of almond orchards in regions with similar environmental conditions as Neyriz of Fars province in Iran as we as in national almond breeding programs.
References
Anonymous, 2019. Protocol for tests on distinctness, uniformity and stability Prunus dulcis (Mill.) D.A. Webb. Document TG/56/4 Corr. Rev, UPOV, Geneva 31 pp.
Alonso Segura, J.M., Ansón, J.M., Espiau, M.T. and Socias i Company, R. 2005. Determination of endodormancy break in almond flower buds by a correlation model using the average temperature of different day intervals and its application to the estimation of chill and heat requirements and blooming date. Journal of the American Society for Horticultural Science, 130(3), pp.308–318. DOI: 10.21273/JASHS.130.3.308
Giordani E., Berti M. and Rauf Yaqubi, M. 2016. Phenotypic characterization of almond accessions collected in Afghanistan. Advances in Horticultural Science, 30(4), pp.207-216. DOI: 10.13128/ahs-20346
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