Walnut Genotypes Research Articles

Rapid in vitro shoot multiplication of the recalcitrant species Juglans nigra L.

Black walnut (Juglans nigra L.) has long been prized for its timber, leading to commercial cultivation and significant breeding efforts for improving marketable traits. Vegetative and in vitro black walnut propagation techniques, however, are variable and highly genotype dependent. Optimizing plant growth regulator type and concentration are integral for developing a successful micropropagation protocol. The addition of meta-topolin (MT) combined with the novel use of a liquid medium has led to the development of a rapid shoot multiplication system. The objective of this research was to develop a reproducible and dependable micropropagation protocol for elite black walnut genotypes. In vitro shoot cultures were established from nodal explants cultured on semi-solid Driver and Kuniyuki walnut (DKW) medium supplemented with 8.9 μM benzyladenine, 0.005 μM indole-3-butyric acid (IBA), 200 mg L−1 casein hydrolysate, 50 mg L−1 adenine hemisulfate, 2 mL L−1 Plant Preservative Mixture™, and 4.1 μM MT. Long-term survival and proliferation of microshoots was achieved when nodal segments of in vitro grown shoots were cultured in liquid initiation medium in 3-L polycarbonate Fernbach-style flasks on a rotary shaker (100 rpm) under a 16-h photoperiod at 25°C. Elongated microshoots (5–7 cm in length) were rooted in a slurry-like medium composed of half-strength DKW medium with 0.11% (w/v) Phytagel™ and coarse vermiculite (2:1, v/v) supplemented with 50 μM IBA for 5 wk. Rooted shoots were acclimatized to ambient culture room conditions, but plantlets did not survive once transferred to the greenhouse.

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

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.

Behavioral Responses of Pityophthorus juglandis (Coleoptera: Curculionidae: Scolytinae) to Volatiles of Black Walnut and Geosmithia morbida (Ascomycota: Hypocreales: Bionectriaceae), the Causal Agent of Thousand Cankers Disease.

Thousand cankers disease (TCD) is a pest complex formed by the association of the walnut twig beetle (WTB), Pityophthorus juglandis Blackman (Coleoptera: Curculionidae: Scolytinae), with the fungal pathogen Geosmithia morbida Kolařík, Freeland, Utley and Tisserat (Ascomycota: Hypocreales: Bionectriaceae). Current monitoring and detection efforts for WTB rely on a pheromone lure that is effective over a limited distance while plant- and fungal-derived volatiles that may facilitate host location remain poorly understood. In this study, we test the hypothesis that adult beetles are attracted to volatiles of black walnut, Juglans nigra L. (Juglandaceae), and the pathogen, G. morbida. We measured the response of beetles to head-space volatiles collected from leaves and stems of 12 genotypes of black walnut and found genotypic variation in the attractiveness of host trees to adult WTB. Volatile profiles of the most attractive genotypes contained more α-pinene and β-pinene, and adult beetles were attracted to both of these compounds in olfactometer bioassays. In bioassays, we also demonstrated that adult WTB are attracted to volatiles of G. morbida. These findings suggest that, in addition to the aggregation pheromone, dispersing WTB potentially use host plant and fungal volatiles to locate suitable larval hosts. Finally, we conducted a field experiment to determine the extent to which ethanol, a common attractant for bark beetles, and limonene, a known bark beetle repellent, influence the behavior of adult WTB to pheromone-baited traps. Although ethanol did not increase trap capture, WTB were repelled by limonene, suggesting that this compound could be used to manipulate and manage WTB populations.

Effect of different growth regulator combinations on growth rate of explants in walnut in vitro studies using MS medium

The present investigation on effect of different growth regulator combinations on growth rate of walnut ( J. regia L.) studies using MS medium was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data were recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. The study also involved establishment of response of elite walnut selections to different plant growth regulators in shoot morphogenesis. Woody species have been found to be far more difficult to clone in vitro than herbaceous plants. Poor response of the explants from mature woody species to in vitro manipulation is usually associated with the problem of browning and explant necrosis. The present studies were conducted on forced explants from three walnut selections (SKUAST 002, SKUAST 008, SKUAST 010). Murashiage and Skoog’s basal medium supplemented with 0.3 mg/l -1 benzylamino purine and 0.1 mg/l -1 indole-3-butyric acid. The growth regulator combinations revealed low to medium effect on the growth rate of explants. The maximum growth rate of 2.49 was found in BAP 0.3 mgl -1 +IBA 0.1 mgl -1 followed by 2.19 in BAP 1.2 mgl -1 +IBA 0.1 mgl -1 as compared to 1.46 and 1.27 in the BAP 0.9 mgl -1 +IBA 0.1 mgl -1 and BAP 0.6 mgl -1 +IBA 0.1 mgl -1 , respectively. This difference was significant in both T 1 (BAP 0.3 mgl -1 +IBA 0.1 mgl -1 ) and T 4 (BAP 1.2 mgl -1 +IBA 0.1 mgl -1 ) as compared to both T 2 (BAP 0.6 mgl -1 +IBA 0.1 mgl -1 ) and T 3 (BAP 0.9 mgl -1 +IBA 0.1 mgl -1 ). Rest of the comparison among the growth regulator combinations were non-significant.

Morphological characterization of walnut genotypes of diverse origin

Walnut (Juglans regia L.) is a major nut crop of temperate region and the existing germplasm available in the country is of seedling origin, thus, contributing towards the large variability in this crop. Therefore, a research study was carried out ICAR-CITH, Srinagar to characterized and decipher the genetic variability among 27 genotypes of Indian walnut (Juglans regia L.) based on morphological characters, viz., growth habit, bearing habit, foliage, fruit and kernel characteristics for further improvement, conservation and utilization. The Erect growth habit was noticed in genotype, viz., CITH-W-12, while semi erect growth habit was noticed in majority of the genotypes. Three types of leaf shapes were recorded i, e narrow elliptic, elliptic, and broad elliptic and based on leaf characteristics all the genotypes could also be categorized viz. pubescence as glabrous, slightly pubescent and pubescent. The genotype was categorized into early, mid and late group based on their fruit maturity duration. High variability was also recorded for fruit shape viz, round, cordate, ovate, long trapezoid, and elliptic. The current findings clearly characterized each genotype and can be identified or grouped individually based on this descriptor. Present study provides the detailed morphological descriptor of walnut which can be utilised for DUS testing of walnut, varietal identification, characterization, registration, documentation etc. The database generated may be useful for comparison against the candidate varieties developed in future

Biochemical changes in terminal buds of three different walnut (Juglans regia L.) genotypes during dormancy break

To the better management of frostbite problem in fruit crops, evaluation of biochemical changes in buds during dormancy break is a key factor. In this study biochemical changes in terminal buds of three different walnut genotypes (early-season, mid-season, and late-season), was investigated during winter dormancy release time. Terminal bud samples were taken from the genotypes in two different times in winter (1st and 20th of March). Variables such as; bud soluble sugars, starch, proline, chlorophyll, total phenolic and protein content as well as catalase (CAT) and guaiacol peroxidase (GPO) enzymes activities were assessed. Analysis of variance ANOVA) revealed significant differences (p ≤ 0.05) for the measured variables and sampling times among the genotypes. The results indicated that the late growth genotype had the highest content of soluble sugars and proline, and the lowest amount of starch and protein (p ≤ 0.05) in comparison with early and mid-season growth genotypes. Different enzymes activities were observed in terminal buds among the genotypes. As sampling time delaying, the content of chlorophyll, CAT and GPO enzymes activity increased, while a decrease in proline and total phenol was observed. The results of this study can be considered to a better understanding of the primary mechanisms of bud dormancy break in walnut to reduce the late spring frost damage problem as well as for using in breeding programs.

Preliminary Evaluation of the Impact of Antioxidants Polyvinylpyrrolidone and Ascorbic Acid on Patch Budding of Persian Walnut

Abstract The purpose of this study is to investigate the effect of antioxidants on the budding success of three walnut genotypes under greenhouse conditions. After stratification, seeds were planted in a greenhouse at the end of autumn. After about 20 months, the seedlings grew up to 80 cm. The budding was done using scions of Z30, Z60, and B21 genotypes. Scions were immersed in polyvinylpyrrolidone (PVP) or ascorbic acid in the concentrations 2, 3, and 4 g·dm−3 for 1 h before budding. Percentage of successful budding was determined after one month. The results showed that genotype significantly affected the percentage of budding success, but no interaction between genotype and treatments was found. The antioxidant solutions significantly affected all the parameters studied in this research. Ascorbic acid with 3 g·dm−3 resulted in the highest percentage of budding success (86.66%); no significant differences were observed with 4 g·dm−3 of ascorbic acid and 3 and 4 g·dm−3 of PVP. Furthermore, antioxidant solutions significantly affected the content of chlorophylls, and 3 g·dm−3 of ascorbic acid resulted in the highest content of chlorophylls in scion leaves.

Persian Walnut Phenology: Effect of Chilling and Heat Requirements on Budbreak and Flowering Date

Walnut production is limited by late-spring frost in many countries. The current research was carried out to evaluate chilling and heat requirement of catkin and terminal buds break on six selected superior walnut genotypes and cultivars (‘C-25’, ‘88-1’, ‘88-2’, ‘Chandler’, ‘Jamal’ and ‘Damavand’). The Utah and accumulation growing degree hours (GDH) models were applied to determine the chilling and heat requirements under field and greenhouse conditions, respectively. ‘Damavand’ cultivar (650 CU) and ‘C-25’ genotype (650-800 CU) had the lowest chilling requirement for terminal bud break. ‘Jamal’ cultivar and ‘C-25’ genotypes had the lowest chilling requirement to break the dormancy of catkins (650–800 CU). ‘Chandler’ cultivar and ‘88-1’ and ‘88-2’ genotypes as late-leafing genotypes/cultivars had the highest chilling and heat requirements to break dormancy of terminal buds (800-1100 CU and 11832-12648 GDH) and catkin (800-950 CU and 11484-12180 GDH). In conclusion, late-leafing genotypes/cultivars had the higher heat requirement than early-leafing genotypes/cultivars. Based on the results, a linear and significant relation was observed between chilling requirement and heat accumulation. Therefore, heat accumulation of buds and catkins was reduced by increase in the amount of chilling requirement. Furthermore, the result revealed that heat accumulation is more important than chilling requirements to estimate walnut budbreak date. The GDH of catkins and terminal buds was decreased with increase in the average temperature during heat accumulation.

Bioefficacy potential of different genotypes of walnut Juglans regia L.

The purpose of investigation was to assess the phytochemical and nutraceutical of walnut in leaf extracts through diverse quantitative and qualitative phytochemical tests followed by array of assays. The screening of 50 elite walnut genotypes which exhibited wide range of discrepancy in terms of phytochemicals as well as their anti-oxidant potential was done. Walnut genotypes displayed maximum divergence in quercetin content (2.86-5.78mg/100g) as represented by cluster analysis. The phenolic rich genotypes exhibiting total phenols (37.61-46.47mg/g GAE) having higher DPPH potential (IP of 32.82-73.50) where as genotypes that accumulate flavonoids/flavanols (5.52-28.48mg/g QE and 4.11-21.76mg/g QE showed immense FRAP activity (418.92-1067.94µM Fe2+/g FW). There was positive correlation between the phenolics content and anti-oxidant potential. The results showed oil content of 50.1-85.08% and kernel percentage 25.21-81.92% of all walnut genotypes. To evaluate the anti-proliferative potential of walnut genotypes, Trypan blue exclusion test, MTT assay and Griess assay was used. Each assay was repeated with different positive controls against a panel of human cancer cell lines viz THP-1, U2OS, IMR-32 and HBL-100 and then compared with the walnut extracts for their efficiency in anti-proliferative activity. The SPS 1 walnut extract at concentration of 500µg/ml exhibited 10% cell viability and with 1000µg/ml walnut extract there was consequent decline towards (6.25%) viability. The results indicated that walnut leaf constitutes an excellent source of effective natural antioxidants and chemo-preventive agents that can act as anti cancer agents.

Exploitation of Walnut (Juglans regia L.) Expressed Sequence Tags for Development of SSR Markers After In Silico Analysis

The walnut (Juglans regia) has been extensively characterized for expressed sequence tags (EST) sequences and currently 6169492 ESTs are available in National Center for Biotechnology Information. Although this is a valuable resource for marker development, the redundancy in sequences makes the mining out of unique candidates for designing markers cumbersome. Keeping this in view, the present study was undertaken with the aim to remove the data redundancy in walnut ESTs and then to develop simple sequence repeats (SSRs) markers. The EST sequences were assembled into a non-redundant set of 85 contigs and 1584 singletons (total sequences 1699), indicating 16.55% reduction in data redundancy. These 1699 sequences were then used to mine out SSR motifs. 132 EST-SSRs were detected, with dinucleotide repeats being predominant (70.45%), followed by trinucleotide repeats (27.27%) and very less frequent hexanucleotides (2.27%). These markers were validated by designing primer pairs. 15 of these designed primers were tested on a group of 37 walnut genotypes. Out of which 7 markers gave robust amplification, generating polymorphism. These findings indicate the usefulness of EST-SSRs in genome analysis. This study further emphasizes the importance of assembly of the vast amounts of data submitted in public databases. Our results have generated a set of non redundant walnut ESTs which is of prime importance for development of marker systems without any repetition or overlapping.

Evaluation of genetic variability among “Early Mature”Juglans regiausing microsatellite markers and morphological traits

Limiting the juvenile phase and reducing tree size are the two main challenges for breeders to improve most fruit crops. Early maturation and dwarf cultivars have been reported for many fruit species. “Early mature” and low vigor walnut genotypes were found among seedlings of Persian walnut. Nine microsatellite markers were used to evaluate genetic diversity among “Early Mature” Persian walnut accessions and provide a comparison with “normal growth” accessions. Six maturation related characteristics were also measured in “Early Mature” samples. Phenotypic traits and diversity indices showed relatively high levels of genetic diversity in “Early Mature” seedlings and indicated high differentiation between individuals. Seedling height, the most diverse phenotypic trait, has an important role in the clustering of “Early Mature” accessions. The “Early Mature” type had higher number of alleles, number of effective allele, and Shannon index compared to the “Normal Growth” group. The two types of studied walnuts had different alleles, with more than half of produced alleles specific to a specific group. “Early Mature” and “Normal Growth” walnuts had 27 and 17 private alleles, respectively. Grouping with different methods separated “Early Mature” and “Normal Growth” samples entirely. The presence of moderate to high genetic diversity in “Early Mature” walnuts and high genetic differentiation with “Normal Growth” walnuts, indicated that “Early Mature” walnuts were more diverse and distinct from “Normal Growth” samples. Moreover, our results showed SSR markers were useful for differentiating between “Early Mature” and “Normal Growth” walnuts. A number of identified loci have potential in breeding programs for identification of “Early Mature” walnuts at the germination phase.

Fat, Fatty Acids and Tocopherol Content of Several Walnut Genotypes

There are seed propagated walnut (Juglans regia L.) populations with the vast genetic variation in different part of Turkey. There are also lots of monoecious and dichogamous genotypes in Turkey due to continuing sexual propagation. In this study, fruits of 19 selected walnut genotypes grown in Kahramanmaraş region were characterized based on their fat, fatty acid and tocopherol contents. The fatty acids content of genotypes were analyzed using Gas Chromatography. Tocopherol analyses such as alpha (α)-Tocopherol, gamma (γ) and beta (β) + delta (δ) were performed by HPLC technique. According to the total fat and fatty acid results, there were differences among genotypes on most of the fatty acids. Total fat ranged from 51.2 to 82.1%, stearic acid from 2.57 to 3.37%, myristic acid from 0.00 to 0.05%, palmitic acid from 6.42 to 7.92%, arachidic acid from 0.00 to 0.16%, linoleic acid from 53.23 to 63.62%, linolenic acid from 10.75 to 15.24%, oleic acid from 14.73 to 24.17% and palmitoleic acid from 0.00 to 0.16%, respectively. The same genotypes were evaluated based on their tocopherol content and (α)-Tocopherol, gamma (γ) and beta (β) + delta (δ) tocopherol were found between 23.47 and 38.04 μg/g, 161.09 and 292.56 μg/g and 16.93 and 32.34 μg/g, respectively.

Estimation of variability and genetic parameters for kernel quality traits (protein and oil content) in the seedling raised natural walnut (Juglans regia L.) population in the Kashmir valley

The present investigation on estimation of variability and genetic parameters for kernel quality traits (protein and oil content) in the seedling raised natural walnut ( Juglans regia L.) population in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data were recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability were observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz. , tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies that the oil content of kernels had a population mean of 62.102 per cent with a range of 50.22-70.00 per cent. Maximum kernel oil content (70%) was found in the walnut selection WS-114 and minimum (50.22%) in the WS-150. Analysis of variance revealed a phenotypic variance of 29.027 as compared to genotypic variance of 8.546 with environmental variance being 20.48. Based on the estimation of components of variance, the phenotypic and genotypic co-efficients of variation were 8.67 and 4.70 per cent, respectively. Heritability (broad sense) was 47.43 per cent and the expected genetic gain as only 5.261 (% of the mean).

Phenotypic variability in the shape of nuts recorded in the seedling raised walnut (Juglans regia L.) population in the Kashmir valley

The present investigation entitled phenotypic variability in the nut shape in the seedling raised natural population of walnut ( J. regia ) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz., tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on nut shape revealed nut shape varied from round to cordate. Majority of the genotypes (56) that represented 36.85 per cent population had round nut shape followed by 36 genotypes (23.69%) that had ovate nut shape; 8 genotypes (5.27%) had triangular nut shape; 10 genotypes (6.58%) had broad ovate nut shape; 7 genotypes (4.60%) had short trapezoid nut shape, 3 genotypes (1.97%) had long trapezoid nut shape, 16 genotypes (10.52%) had broad elliptic nut shape and the remaining 13 genotypes (8.55%) had elliptic nut shape.

Diversity for shell strength in the natural population of walnut (Juglans regia L.) in the Kashmir valley

The present investigation entitled diversity for shell strength in the natural population of walnut ( Juglans regia L.) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz. , tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on shell strength revealed substantial variability among the seedling raised walnuts genotypes in Kashmir valley revealed that shell strength of walnut revealed that shell strength of walnut genotypes under study varied from papery to strong. Ten genotypes (6.58%) were found having papery shell, 41 genotypes (26.98%) had weak shell strength, 76 genotypes (50.00%) possessed intermediate shell strength and 25 genotypes (16.44%) were found to have strong shell strengthnut genotypes under the present study.

Diversity for shell seal in the natural population of walnut (Juglans regia L.) in the Kashmir valley

The present investigation entitled diversity for shell texture in the natural population of walnut ( Juglans regia L.) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz. , tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on shell texture revealed substantial variability among the seedling raised walnuts genotypes in Kashmir valley revealed that shell texture of walnut genotypes under the present study varied from very smooth to rough shell texture. Seventeen genotypes (11.18%) were found to possess rough shell texture. Seventy five genotypes (49.34%) had smooth shell texture, 52 genotypes (34.21%) had medium shell texture and 8 genotypes (5.27%) were very smooth shell textured.

Diversity for branching habit in the natural population of walnut (Juglans regia L.) in the Kashmir valley

The present investigation entitled diversity for growth habit in the natural population of walnut ( Juglans regia L.) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz. , tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on .branching habit revealed substantial variability among the seedling raised walnuts genotypes in Kashmir valley. In this study it was found that 30 genotypes (19.73%) possessed sparse branching habit, 57 genotypes (37.50%) exhibited intermediate branching habit and 65 genotypes (42.77%) had dense branching habit.

Diversity for leaflet shape in the natural population of walnut (Juglans regia L.) in the Kashmir valley

The present investigation entitled diversity for leaflet shape in the natural population of walnut ( Juglans regia L.) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz. , tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on leaflet shape revealed substantial variability among the seedling raised walnuts genotypes in Kashmir valley. In this study it was found that 46 genotypes (30.26%) had narrow elliptic leaflets, 39 genotypes (25.65%) had elliptic leaflet and 67 genotypes (44.09%) were with broad elliptic leaflet shape.

Diversity for growth habit in the natural population of walnut (Juglans regia L.) in the Kashmir valley

The present investigation entitled diversity for growth habit in the natural population of walnut ( Juglans regia L.) in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz., tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. Studies on growth habit revealed substantial variability among the seedling raised walnuts genotypes in Kashmir valley fifty four genotypes (35.52%) had erect growth habit and another 54 genotypes (35.52%) had semi-erect growth habit, while remaining 44 genotypes (28.96%) had spreading growth habit.

Estimation of variability and genetic parameters for nut characters (weight, diameter and length) in the seedling raised natural walnut (Juglans regia L.) population in the Kashmir valley

The present investigation entitled estimation of variability and genetic parameters for nut characters (weight, diameter and length) in the seedling raised natural walnut ( Juglans regia L.) population in the Kashmir valley was carried out in order to document the available genetic variability in walnut germplasm and to select elite walnut genotypes possessing superior attributes and quality traits. During the survey, data was recorded on one hundred fifty two (152) walnut trees growing in different areas of Kashmir valley. Remarkable variability was observed in seedling walnut trees for different morphological, nut and kernel characters. Similarly, variations were also reported for other characters viz., tree vigour, growth habit, branching habit, leaflet shape, shoot colour, nut shape, shell texture, shell colour, shell seal, shell strength, shell integrity, kernel shrivel and kernel colour. studied the nut length varied from 30.0-60.0 mm with a population mean of 55.62 ± 3.28mm. The phenotypic and genotypic variance was 605.14 and 427.56, corresponding to their co-efficients of variation to the extent of 44.25 and 37.17 per cent, respectively. Heritability (broad sense) and expected gain (% of the mean) was 70.65 per cent and 64.36, respectively. Nut weight revealed a population mean of 14.48 ± 2.54 g with a range of 8.50-30.0 g. The phenotypic (18.785) and genotypic (12.760) variance when translated into their respective co-efficients of variation gave the estimate of 27.98 and 23.02 per cent, respectively. Broad sense heritability was 67.9 per cent and expected genetic gain (% of the mean) as 39.15.