Correlations between Some Horticultural Traits in Walnut

Amiri, Reza; Vahdati, Kourosh; Mohsenipoor, Somayeh; Mozaffari, Mohammad Reza; Charles, Leslie

doi:10.21273/hortsci.45.11.1690

Cited by 60 publications

(37 citation statements)

References 13 publications

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“…Because of the high heritability, fruit breeders are interested in pomological traits in walnut-breeding programs. However, knowledge of strong associations between pomological traits and other characteristics can guide appropriate selection schemes for walnut-breeding programs (Amiri et al, 2010). In this study, a significant and positive correlation was observed between nut and kernel weight and between both of them and NSI.…”

Section: Resultsmentioning

confidence: 53%

“…In addition, harvesting date had a significant negative correlation with kernel color. Yield (bearing) is the main objective of breeding programs of fruit trees including walnut (Amiri et al, 2010). A heat map of spearmen correlations between all measured traits, showed that bearing had a positive correlation with budbreak date, lateral bearing (P < 0.01), nut and kernel weight and NSI (P < 0.05).…”

Section: Resultsmentioning

confidence: 99%

“…Protogyny is an important trait for genotypes as a pollinizer for commercial cultivars (Germain, 1990). Because of its direct impact on production, lateral bearing is considered as a main trait for the selection of walnut superior genotypes (Amiri et al, 2010). Lateral bearing of the studied superior genotypes was more than 50%.…”

Section: Discussionmentioning

confidence: 99%

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Genome Size: A Novel Predictor of Nut Weight and Nut Size of Walnut Trees

Sarikhani¹,

Arzani²,

Karimzadeh³

et al. 2018

horts

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Plant genetic diversity is the fundamental of plant-breeding programs to improve desirable characteristics. Hence, evaluation of genetic diversity is the first step in fruit-breeding programs. Accordingly, the current study was carried out to evaluate 25 superior walnut genotypes in respect of phenotypic and cytological characteristics. For this purpose, 560 walnut genotypes in southwest of Iran were evaluated based on UPOV and International Plant Genetic Resources Institute (IPGRI) descriptor. After a 2-year primary evaluation, 25 superior genotypes were selected for future phenotypic and genome size assessment. Flow cytometry was used to estimate genome size of the selected superior genotypes. A high genetic diversity was found in walnut population collected from the southwest of Iran. The selected superior genotypes had high yield, lateral bearing, thin-shell thickness (0.90–1.64 mm), high nut (12.54–19.80 g) and kernel (7.02–9.91 g) weight with light (L) to extra light (EL) kernel color which easily can be removed from the shell. Also, FaBaCh2 genotype turned out to be protogynous being important as a pollinizer cultivar. In addition to extensive phenotypic analysis, genome size was determined. The studied genotypes were diploid (2n = 2x = 32) and varied in genome size from 1.29 (FaBaAv2) to 1.40 pg (FaBaNs12). Correlation analysis showed that lateral bearing, budbreak date, nut size, and weight were the main variables contributing to walnut production. A linear relationship was found between genome size and nut weight (r = 0.527**), kernel weight (r = 0.551**), and nut size index (NSI) (r = 0.487**). Therefore, genome size can be considered as a strong and valuable tool to predict nut and kernel weight and nut size.

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 99%

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Genome Size: A Novel Predictor of Nut Weight and Nut Size of Walnut Trees

Sarikhani¹,

Arzani²,

Karimzadeh³

et al. 2018

horts

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“…Lateral bearing is a crucial trait in walnut breeding since it contributes to increased yield [42]. Fruiting at lateral positions on shoots was originally introduced into California from the cultivar 'Payne', which is in the background of all current varieties released by the Walnut Improvement Program of the University of California, Davis [4].…”

Section: Genetic Bases For the Expression Of Lateral Bearingmentioning

confidence: 99%

Association and linkage mapping to unravel genetic architecture of phenological traits and lateral bearing in Persian walnut (Juglans regia L.)

et al. 2020

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Background: Unravelling the genetic architecture of agronomic traits in walnut such as budbreak date and bearing habit, is crucial for climate change adaptation and yield improvement. A Genome-Wide Association Study (GWAS) using multi-locus models was conducted in a panel of 170 walnut accessions genotyped using the Axiom™ J. regia 700 K SNP array, with phenological data from 2018, 2019 and legacy data. These accessions come from the INRAE walnut germplasm collection which is the result of important prospecting work performed in many countries around the world. In parallel, an F 1 progeny of 78 individuals segregating for phenology-related traits, was genotyped with the same array and phenotyped for the same traits, to construct linkage maps and perform Quantitative Trait Loci (QTLs) detection.Results: Using GWAS, we found strong associations of SNPs located at the beginning of chromosome 1 with both budbreak and female flowering dates. These findings were supported by QTLs detected in the same genomic region. Highly significant associated SNPs were also detected using GWAS for heterodichogamy and lateral bearing habit, both on chromosome 11. We developed a Kompetitive Allele Specific PCR (KASP) marker for budbreak date in walnut, and validated it using plant material from the Walnut Improvement Program of the University of California, Davis, demonstrating its effectiveness for marker-assisted selection in Persian walnut. We found several candidate genes involved in flowering events in walnut, including a gene related to heterodichogamy encoding a sugar catabolism enzyme and a cell division related gene linked to female flowering date. Conclusions: This study enhances knowledge of the genetic architecture of important agronomic traits related to male and female flowering processes and lateral bearing in walnut. The new marker available for budbreak date, one of the most important traits for good fruiting, will facilitate the selection and development of new walnut cultivars suitable for specific climates.

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“…Additionally, recent studies have shown that shell thickness is significantly positively correlated with nut weight, which itself is significantly negatively correlated with kernel percentage (Arzani et al, 2008;Zhao et al, 2007). Shell thickness was one of the main variables accounting for kernel percentage and should be considered in breeding (Amiri et al, 2010). In addition, shell structural features such as shape, thickness, and texture, were the most important parameters affecting kernel extraction quality in nuts (Amiri et al, 2014;Ghafari et al, 2011).…”

mentioning

confidence: 99%

The Relationship among the Structural, Cellular, and Physical Properties of Walnut Shells

Zhao¹,

Niu²,

Yun³

et al. 2019

horts

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The role of the walnut (Juglans regia L.) shell in nut development, transportation, cleaning, and storage is often ignored. The shell suture seal and thickness are directly associated with kernel characteristics. In the present study, shell differentiation and microstructure were observed with an optical microscope using paraffin-sectioning and cryosectioning. The results showed that the parenchymal cells of the endocarp began to differentiate into sclerenchymal cells from 49 d after flowering (DAF), and the entire process continued until fruit maturation. The mature shell consists of three parts, including the sclereid layer (L1), sclerenchymal cell layer (L2), and shrunken cell layer (L3), from the outside to the inside. The shell thickness, suture seal grade, and mechanical strength were evaluated, as well as the lignin, cellulose, and phenolic compounds of the shell. Suture seal grade was positively correlated with lignin content, shell thickness, and L1 thickness and negatively correlated with shell cell diameter. Similarly, the mechanical strength of the shell was positively correlated with lignin content and L1 thickness. 'Qingxing' fruits were subjected to two treatments, namely, 30% shading and 70% shading, from 10 d after anthesis to maturity, with no shading used as control. After harvesting in September, nutshell sections showed thinner shells, with decreased contents of lignin and polyphenols, obtained under shaded conditions, and two of the three parts of the shell changed dramatically. The thinning of L1 and thickening of L3 eventually led to a thinner shell. The aim of this study was to evaluate the relationship among the shell structure, cellular components, and physical properties and provide a theoretical basis for cultivar breeding, rational planting density, and regulation of shell development.

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Correlations between Some Horticultural Traits in Walnut

Cited by 60 publications

References 13 publications

Genome Size: A Novel Predictor of Nut Weight and Nut Size of Walnut Trees

Genome Size: A Novel Predictor of Nut Weight and Nut Size of Walnut Trees

Association and linkage mapping to unravel genetic architecture of phenological traits and lateral bearing in Persian walnut (Juglans regia L.)

The Relationship among the Structural, Cellular, and Physical Properties of Walnut Shells

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