Pear Genotypes Research Articles

Phosphorus effect on the production and nutritional value of cactus genotypes in a region of semi-arid climate

The study aims evaluate the effect of phosphate fertilization on yield, chemical composition and in situ degradability of different cactus pear genotypes under semi-arid climate conditions. A randomized complete block design was adopted, the plots being three cactus pear genotypes [Doce and Baiano (Nopalea cochenillifera) and Mexicano (Opuntia tuna)] and the subplots being four phosphorus levels in the soil (0; 30; 60 and 90 kg P ha-1 year). The highest total green forage mass yield (TGFM) was observed in the genotype Mexicano with 87,830 ± 4,220 kg ha-1, and there was an increase of 34,630 kg ha-1 of TGFM when 90 kg of P ha-1 was used. The neutral detergent fiber content showed linear response with increase of 0.285 g kg-1 for each kg of phosphorus applied. Regarding the genotype Doce, the highest degradation values of fractions “a”, "b" and "c" of the dry matter (DM) were observed at the levels 90, 0 and 90 kg P ha-1 year, respectively, and of the crude protein (CP) at the levels 0; 0 and 60 kg P ha-1 year, respectively. Phosphate fertilization increases yield and improves the nutritional value of cactus genotypes in region of semi-arid climate.

Transferability of apple and pear SSRs to other temperate pome fruit crops of family Rosaceae

Extensive use of simple sequence repeat (SSR) is facilitated if loci would be transferable across species even in closely related genera to overcome high cost and efforts involved in their development as major constraints. In the present study, apple and pear genomic microsatellite primer pairs were used to amplify SSR loci in apple, pear, quince and loquat genotypes, respectively. Already reported SSRs were selected based on their polymorphic survey for successful amplification with at least one polymerase chain reaction (PCR) product of the approximate size expected for a homologous locus screened among apple and pear genotypes for further transferability exploration across other temperate pome fruit crops, respectively. Highest transferability of apple and pear SSR, 61.53 % and 73.33 % was observed in closely related quince and apple genotypes, respectively. This indicated that primer binding sites between these two closely related genera, Malus and Pyrus, are fairly well conserved. Maximum transferability rate was found to be 93.33 % and 80.00 % across all the subjected genotypes for primer CH05D11 and TSUenh016 in apple and pear, respectively. The transferability of markers is based on genomic similarity, and can reflect the relationship of genome collinearity and even evolution between species. This high level of transferability of apple and pear SSRs to other temperate pome fruit crops indicated their promise for application to future molecular screening, map construction, and comparative genomic studies, etc.

Chemical composition, fractionation of carbohydrates and nitrogen compounds, ruminal degradation kinetics, and in vitro gas production of cactus pear genotypes

Abstract The aim of this study was to evaluate the chemical composition, fractionation of carbohydrates and nitrogen compounds, degradation parameters, and in vitro ruminal fermentation of cactus pear genotypes. The experiment was conducted in a completely randomized design with 4 cactus pear genotypes and 4 replicates. The evaluated cactus pear genotypes were: Miúda (Nopalea cochenillifera Salm Dyck), IPA Sertânia (Nopalea cochenillifera), Gigante (Opuntia ficus indica Mill), and Orelha de Elefante Mexicana (Opuntia stricta Haw), all in natura. Samples were randomly collected at different points in the experimental area. Whole plants were collected 24 months after field crop establishment. N. cochenillifera Salm Dyck presented the highest dry matter, acid detergent insoluble protein, non-fibrous carbohydrate, total digestible nutrients, digestible energy, total carbohydrates, and fractions A + B1 (P<0.05), while presenting lower neutral detergent fiber corrected for ash and protein, acid detergent fiber, and cellulose in relation to the other genotypes studied (P<0.05). The in vitro true digestibility of neutral detergent fiber was high for the genotypes N. cochenillifera Salm Dyck and N. cochenillifera Dyck, which also presented high in vitro total gas production (P<0.05). The cactus pear genotypes show adequate chemical characteristics to be composed part of diets offered to ruminants. However, supplementation is necessary to increase the dry matter and fiber contents. The Nopalea cochenillifera Salm Dyck genotype presented the highest proportions of total digestible nutrients, non-fibrous carbohydrates, non-protein nitrogen, unavailable nitrogen fraction total, and high gas production in relation to the other analyzed genotypes 24 months after field crop establishment.

Peculiarities of the juvenile period of the native Chechen genotypes of willow leaf pear (Pyrus salicifolia Pall.)

The results of the study of the duration of the juvenile period of indigenous Chechen willow leaf pear genotypes (Pyrus salicifolia Pall.) are given in connection with the acceleration of the breeding process and the use of selected forms in pear breeding for high precocity. The studies were carried out in 2016-2019 at OOO “Orchards of Chechnya” in accordance with the Agreement on creative cooperation with the Russian Research Institute of Fruit Crop Breeding. The work was carried out in accordance with generally accepted programs and methods. The objects of the study were one-year and two-year-old pear seedlings obtained from sowing seeds of selected dwarf and low-growing local Chechen forms of willow pear (P. salicifolia Pall.), laying fruit buds on annual growths and seedlings of Caucasian pear (P. caucasica Fed.), 20 500 pcs. of each specie. The aim of the research was to study the potential of precocity of willow pear seedlings and to reveal of selected forms with the greatest degree of this trait. Stratified seeds were sown in the sowing department of the OOO “Orchards of Chechnya” production nursery in April, 2017. The seedlings were grown according to the common technology in dryland conditions on the plot with chestnut soil. The first fl owering of plants was noted in the spring, 2019. As a result of the research, for the first time on a large number of the experimental material it was found that in the off spring of the indigenous Chechen willow leaf pear genotypes, the selection of a little more than 2% of seedlings with a very short juvenile period (2 years) was possible. They are of great interest in accelerating the breeding process and in the selection of new pear varieties with high precocity. 20 willow leaf pear genotypes were selected for the further use in breeding for high precocity and as sources of the trait of short juvenile period.

Classification, identification and testing of pear genotypes applying ask-analysis method

Classification, identification and testing of pear genotypes applying ask-analysis method

Copolymerized Natural Fibre from the Mesocarp of Orbignya phalerata (Babassu Fruit) as an Irrigating-Fertilizer for Growing Cactus Pears.

Cactus pears face challenges due to global climate change, which is leading to in-depth research to monitor and increase their water activity. The objective of this study was to evaluate the use of the natural test hydrogel (TH) from Orbignya phalerata fibre as nutrients and water for growing cactus pear genotypes (“Baiana” and “Doce” [Nopalea cochenillifera], ‘Gigante’ [Opuntia fícus-indica], and “Mexican Elephant Ear” [Opuntia stricta]) compared to the use of commercial hydrogel (CH), which is based on polymers composed of polyacrylamide, and a treatment without the use of hydrogel (WH). A completely randomized design was used, in a factorial scheme (4 × 3), with four genotypes of cactus pear and three forms of hydration, with five replications. The number and area of cladode was greatest (p < 0.01) in plants with CH and TH irrigation-fertilization in the ‘Doce’ cactus genotype. The dry biomass of the cladode and root in the ‘Gigante’ cactus genotype was greatest (p < 0.01) in the treatments with CH and TH irrigation-fertilisation. The ‘Baiana’, ‘Doce’, and ‘Gigante’ cactus genotypes exhibited more (p < 0.01) dry matter content with the TH irrigation-fertilisation. The highest (p < 0.01) neutral detergent fibre content was observed in the ‘Baiana’ and ‘Doce’ cactus genotypes when irrigation occurred with WH treatment, and the highest acid detergent fibre content in the ‘Gigante’ genotype. The copolymerized natural fibre from the mesocarp of Orbignya phalerata (babassu fruit) induced a better growth and chemical composition of cactus pear genotypes than the hydrogel based on polymers composed of polyacrylamide.

Investigation on phenological stages, blooming behaviour and pollen functional ability of different pear genotypes under Kashmir conditions

The present investigation was conducted in the Experimental Farm of Division of Fruit Science, Sher-e-Kashmir University of Agricultural Science & Technology of Kashmir, Shalimar, Srinagar, Jammu & Kashmir during the year 2017. Nine pear genotypes viz., William Bartlett, Fertility, Chinese Sandy Pear, Clapp’s Favourite, Max Red Bartlett, Kings Pear, Beurre de Amanalis, Carmen and Abate Fetel were evaluated. The study showed significant differences among all the genotypes in all the phenological stages, blooming behaviour and pollen functional ability. The blooming pattern of genotypes revealed that “Chinese Sandy Pear” and “Kings Pear” were first to come into flowering followed by “Clapp’s Favourite” and “Beurre de Amanalis” whereas, “William Bartlett”, “Max Red Bartlett”, “Fertility”, “Carmen” and “Abate Fetel” were observed to be late bloomers. The flowering duration (15 days) was longest in “Fertility” followed by 14.67 and 14.22 days in “William Bartlett” and “Max Red Bartlett”, respectively and shortest (11.45 days) in “Chinese Sandy Pear”. The highest pollen viability (84.07%) and germination (73.25%) was observed in “William Bartlett”.

Resilience of cactus pear genotypes in a tropical semi-arid region subject to climatic cultivation restriction

The cactus pear has demonstrated productive potential in arid and semi-arid regions due to its photosynthetic process of crassulacean acid metabolism. Thus, this study aimed to evaluate agronomic characteristics and chemical composition of three genotypes of cactus pear at different locations of a tropical semiarid region classified as non-suitable for cactus pear cultivation. A completely randomized design in a factorial arrangement (3 × 7) (three genotypes of cactus pear [Miúda, Baiana (Nopalea cochenillifera) and Orelha de Efefante Mexicana - OEM (Opuntia stricta)] and seven locations) was used. The climatic conditions characterized an environment that restricts the growth of cactus pear genotypes, mainly due to the air relative humidity values. All morphological characteristics of the cactus pear genotypes were influenced by the interaction genotype x location, with higher expression of the characteristics on the different genotypes under hot semi-arid climate and tropical wet and dry climate. An effect of the interaction genotype x location was observed (p < 0.05) on water use efficiency, water accumulation and carrying capacity, where the highest values were observed for genotype Baiana at location 1. Also, there was influence of the interaction genotype x location over the chemical composition of the cactus pear. The cultivation of cactus pear is recommended under restricted climatic conditions in semi-arid tropical regions, especially the genotype Baiana, based on growth factors, biomass production and chemical composition.

Characterisation of microsatellite loci in Sardinian pears (Pyrus communis L. and P. spinosa Forssk.)

The Sardinian pear germplasm is an important resource of genetic diversity that can be used for increasing data on European pear germplasm, to optimise the efficiency of the association studies within the genome and to identify genomic regions that control the main horticultural traits. A set of 108 Sardinian pear genotypes, composed of 81 Pyrus communis cultivars, 24 wild populations of P. spinosa and three international reference cultivars, was analysed using nine SSR markers to assess the genetic diversity of Sardinian pears, determine their genetic structure and study the cases of synonymies and homonymies. The comparison of SSR profiles indicated four groups of diploid accessions with the same SSR profile. The alignment with the Sardinian dataset, pointed out a clear genotype distinctiveness. For all studied SSR loci, 15 specific rare alleles were identified, with a minimum of two alleles found in the database of analysed accessions for the SSRs EMPc11 and EMPc117. The overall allelic diversity revealed a high polymorphism in the analysed Sardinian germplasm. The structure analysis allowed us to identify four gene pool groups (Sardinian cultivars, Japanese cultivars, late-ripening cultivars and, the most famous, standard cultivars). These results were confirmed by Evanno’s △k statistical analysis which has shown unequivocally that k = 4 (△k = 150) is the most likely stratification level of the cluster. The Q values of P. communis and P. spinosa accessions have confirmed an allelic interchange between wild and cultivated genotypes.

Methods of storing cactus pear genotypes for animal feeding

The objective of this study was to evaluate storage methods of cactus pear as a way of conservation for use in animal feeding. The randomised experimental design composed twelve treatments and three replications. Three cactus pear genotypes, Nopalea cochenillifera genotype Doce and Baiana and Opuntia tuna genotype Orelha de Elefante Mexicana (OEM), were stored in natura (0, 30 and 60 days after harvest) and as silage. There was a significant difference (p < 0.05) on the chemical and mineral composition of the material stored in natura versus silage. OEM cactus pear presented the highest crude protein content when stored in natura for 0, 30 and 60 days. The highest lignin content was observed in cactus pear OEM when stored in natura for 30 and 60 days after harvest. Macro- and micronutrient contents were within the recommended ranges for ruminant feeding regardless of the cactus pear genotype and storage method. The cactus pear genotypes Doce and Baiana, and genotype OEM can be stored as silage and in natura form for up to 60 days after harvest without compromising the quality of the feed for ruminants.

OCCURRENCE OF PESTS AND DISEASES IN CACTUS PEAR GENOTYPES / OCORRÊNCIA DE PRAGAS E DOENÇAS EM GENÓTIPOS DE PALMA FORRAGEIRA

The objective was to evaluate the occurrence of pests, diseases and mortality rate in nine genotypes of cactus pear ( Nopalea cochenillifera ) destined for forage production. The genotypes were implanted in a complete randomized block design, with nine treatments and three replications. After 330 days of cultivation, the occurrence of pests and diseases and verification of plant mortality were carried out. Among all the pests and diseases observed in this experimental trial, the most prevalent disease regardless of the evaluated genotype was the anthracnose stain “ Colletotrichum gloeosporioides ” (49.20%) and the less frequent diseases were the resine “ Dothiorella ribis ” (6.87%) and soft rot “ Erwinia carotovora ” (2.58%). The only occurrence pest was the cochineal in scales “ Diaspis echinocacti ” (22.69%). The Texas (V13) and Negro Michoacan (F07) genotypes showed the highest occurrence of pests and diseases, from 50% of the total plants, followed by anthracnose stain and cochineal in scales. On the contrary, the genotypes Tamazunchale (V12) and California (V14) were not affected by any pest or disease. It was observed that the genotypes Nopalea Uruapan (V20) and Blanco San Pedro (V19), had a lower occurrence of pests and diseases, less than 20% of the total plants. The genotypes that presented the highest mortality rate were Texas (V13), Blanco San Pedro (V19) and Polotitlan (V09), with 80, 70 and 65% mortality rate, respectively. The genotypes Nopalea Uruapan (V20) and California (V14) had the lowest mortality rate (20 and 35%), respectively. The genotypes that were least affected by pests and diseases and had the lowest mortality rate are Tamazunchale (V12), California (V14) and Nopalea Uruapan (V20).

The selection of local summer pear genotypes in Malatya province

Anadolu pek çok meyve türünde olduğu gibi armudun da gen merkezleri arasındadır. Yukarı Fırat havzasında bulunan ve ülkemizin önemli meyvecilik merkezlerinden olan Malatya ilinde standart armut çeşitlerinin yanı sıra çok sayıda mahalli çeşitler de yetiştirilmektedir. Bu mahalli çeşitler ıslah çalışmaları için önemli genetik kaynak oluşturmaktadır. Malatya ilinde yetiştirilen yerel yazlık armutların seleksiyonu amacıyla 2014-2017 yılları arasında yürütülen bu çalışmada ilk olarak ön seleksiyonla sağlıklı gelişme gösteren verimli ve kaliteli meyvelere sahip ağaçlar işaretlenmiştir. Daha sonra, belirlenen bu ağaçlardan hasat döneminde alınan meyve örneklerinde pomolojik analizler gerçekleştirilmiştir. Elde edilen verilerin tartılı derecelendirme metoduyla değerlendirilmesi sonunda üç genotip (44.13.07, 44.08.01, 44.06.14) ümitvar olarak belirlenmiştir. Ümitvar genotiplerde meyve ağırlığı 121.80 (44.08.01) -163.98 g (44.06.14), meyve eti sertliği 4.18 (44.13.07) - 8.35 kg/cm2 (44.08.01), SÇKM oranı %13.60 (44.13.07) - %15.40 (44.08.01), TEA değeri % 0.18 (44.06.14) - % 0.21 (44.13.07) ve meyve suyu pH’sı ise 3.95 ( 44.13.07) - 4.82 ( 44.08.01) arasında değişmiştir. Çalışmada ümitvar bulunan genotiplerin kumsuz, tat durumu ve yeme kalitesi bakımından üstün özelikte oldukları belirlenmiştir. Çalışma sonunda belirlenen ümitvar bireyler muhafaza altına alınmak amacıyla Kayısı Araştırma Enstitüsü Müdürlüğü armut koleksiyon parseline taşınmıştır.

Screening of Pyrus pyrifolia genotypes for resistance to Alternaria alternata

Black spot disease (BSD) caused by the fungus Alternaria alternata is one of the most devastating diseases in pear. Most cultivated sand pear (Pyrus pyrifolia Nakai) and its hybrids are susceptible to this disease, and the main measures for the disease control are bagging and spraying of fungicides. Here, we evaluated the resistance of various P. pyrifolia genotypes to the disease by both natural infection and artificial inoculation during the years of 2013–2015. Among the 331 genotypes, 9 were highly resistant (HR) to A. alternata. Multiple linear stepwise (MLS) regression analysis indicated that the susceptibility of P. pyrifolia to A. alternata was correlated with stalk length, branching ability, duration of fruit development, fruit weight and soluble solid content. Totally 11 simple sequence repeat (SSR) markers, which selected from previous RNA-Seq data, were used to check their contributions to the disease resistance and for analysis of genetic diversity. The mean polymorphism information content was 0.66, indicating a high level of SSR polymorphism. The proportions of SSR loci 6167B and 15091C were higher in disease-resistant varieties, while those of SSR loci 6484A, 6643A and 12717A were higher in disease-susceptible varieties. This study provides the genetic variations of pear genotypes resistant to A. alternata, which could contribute to future breeding of BSD resistant varieties.

Chemical composition and spine occurrence in cactus pear genotypes

The spineless cactus 'Orelha de Elefante Mexicana' (Opuntia sp.) is a genotype resistant to cochineal carmine pest (Dactylopius opuntiae Cockerell). However, this clone has many spines, making it difficult to grasp and chew as forage, limiting animal consumption. In addition, the spines cause difficulty in harvesting and cultivation. The objective of this work was to evaluate the chemical composition, digestibility and occurrence of spines of genotypes of 'Orelha de Elefante Mexicana' (Opuntia sp.), and the correlation between chemical composition and digestibility with occurrence of spines. The experiment was carried out at the Experimental Research Station of Agricultural Institute of Pernambuco, located in Arcoverde, Brazil from January 2014 to June 2015. The genotypes Lisa 1, Lisa 2, Seg CV, Seg 1, Seg 2, Seg 3, Seg 4, Seg 5, and Seg 6 were produced in previous selections from seeds of the 'mother-plant'. Soil of the experimental area is classified as Regosol, and rainfall during the experimental period was 771 mm. Fertilization was performed with 20 t organic matter ha(‑1) year(‑1) using cattle manure. Planting was done in January 2014, using spacing of 1.4×0.5 m and a completely randomized design with 10 replications of one plant each. Variables analyzed were chemical composition, digestibility, and occurrence of spines. Evaluations were performed on secondary cladodes of 18-month-old plants. Lisa 1 and Lisa 2 presented greater dry matter (DM) concentration than other genotypes. When compared with Seg CV, the genotypes Lisa 1 and Lisa 2 presented greater DM and in-vitro dry matter digestibility (IVDMD), and lower neutral detergent fiber (NDF) and acid detergent fiber (ADF). Genotypes showed variability in chemical composition, digestibility, and the presence of spines. The presence of spines and glochids showed positive correlation with NDF and ADF concentration and negative correlation with IVDMD and DM, but did not affect crude protein concentration.

Seed Characteristics of Wild Pear Genotypes from the in situ Population of the Banja Luka Region

Wild pear (Pyrus communis var. piraster (L.) Ehrh.) is widely used as a generative rootstock for pear grafting. Seeds for the production of this rootstock should be taken from the registered mother plants. The aim of this research was to select mother plants in wild pear population from three localities (Banja Luka, Manjača, and Potkozarje). Fruit bearing regularity of selected trees was observed from 2012-2016, and the number of seeds per fruit was analysed in 2013, 2015 and 2016. Seed germinability and vitality analysis was carried out on 14 selected tress (genotypes). Seed germinability was tested according to the ISTA guideline. Seed vitality was determined by the tetrazolium test (TT). Accessions from Banja Luka locality expressed the highest fruit production. The highest number of seeds was determined in the genotypes marked as No. 6 and No. 21, amounting to 7.53 and 7.21 seeds, respectively. Seeds of the tested wild pears have shown good vitality. The highest seed vitality and germination of 92% was obtained from the accession No. 20. On the basis of the results, accessions marked with numbers: '6', '8', '20', '25', '31' and '32' can be used as mother plants for pear rootstock production.

Selection of Local Winter Pear Genotypes Grown in Malatya

Malatya ilinde&#x0D; yetiştirilen yerel kışlık armutların seleksiyonu amacıyla 2014-2017 yılları&#x0D; arasında yürütülen bu çalışmada ilk olarak ön seleksiyonla sağlıklı gelişme&#x0D; gösteren verimli ve kaliteli meyvelere sahip ağaçlar işaretlenmiştir. Daha&#x0D; sonra belirlenen bu ağaçlardan pomolojik analizler için hasat döneminde meyve&#x0D; örnekleri alınmıştır. Pomolojik analizlerden elde edilen verilerin&#x0D; değerlendirilmesinde değiştirilmiş tartılı derecelendirme metodu&#x0D; kullanılmıştır. Değerlendirme sonucunda yedi genotip (44.06.02, 44.06.08,&#x0D; 44.11.03, 44.11.21, 44.11.14, 44.11.13, 44.13.06) ümitvar olarak&#x0D; belirlenmiştir. Ümitvar bireylerde meyve ağırlığı 128.17&#x0D; (44.11.13 ) - 209.73 g (44.11.14), meyve eti sertliği 4.90 (44.13.06) - 9.92&#x0D; kg/cm2 (44.06.08)&amp;nbsp; ve SÇKM&#x0D; oranı ise % 12.85 (44.06.08) - % 19.40 (44.11.13) arasında değişmiştir.&#x0D; Kumluluk durumu bakımından ümitvar genotiplerin üçü orta derecede kumlu&#x0D; (44.11.14, 44.11.21, 44.11.13), dördü kumsuz (44.06.08, 44.13.06, 44.11.03,&#x0D; 44.06.02) olarak değerlendirilmiştir. Yeme kalitesi bakımından bir genotip&#x0D; (44.11.03) orta, altı genotip ise&amp;nbsp;&#x0D; (44.06.08, 44.13.06, 44.06.02, 44.11.14, 44.11.21, 44.11.13) iyi&#x0D; kalitede belirlenmiştir. Çalışma sonunda belirlenen ümitvar bireyler seleksiyon&#x0D; çalışmasının ikinci aşamasında materyal olarak kullanılmak üzere Kayısı&#x0D; Araştırma Enstitüsü Müdürlüğü armut koleksiyon parselinde koruma altına&#x0D; alınmıştır.

A Pyrus communis gene for p-hydroxystyrene biosynthesis, has a role in defense against the pear psylla Cacopsylla biden

Styrene analogs are known to be naturally synthesized in the leaves of pears and in other plant species, including several trees in the Styracaceae family. Styrene analogs are potential contributors to the aroma of wine, perfumes, pharmaceuticals, and other fermented foods and beverages. In addition, styrene analogs perform important ecological functions such as insecticidal and antifeedant activities against insects. We showed here that exogenous applications of styrene and p-hydroxystyrene caused a dramatic reduction the number of eggs laid by psylla and of subsequent nymph survival. Despite their importance specific reactions that lead to the biosynthesis of the styrene analogs in pear are unknown. To identify genes involved in the synthesis of these metabolites, existing genome databases of the Rosaceae were screened for pear genes with significant sequence similarity to bacterial phenolic acid decarboxylase. Herein described are the isolation and characterization of a pear phenolic acid decarboxylase, designated PyPAD1, which catalyzed the decarboxylation of p-coumaric acid and ferulic acid to p-hydroxystyrene and 3-methoxy-4-hydroxystyrene respectively. Its apparent Km values for p-coumaric acid and ferulic acid were 34.42 and 84.64 μM, respectively. The PyPAD1 preferred p-coumaric acid to ferulic acid as a substrate by a factor of 2.4 when comparing catalytic efficiencies in vitro. Expression analysis of PyPAD1 showed that the gene was transcribed in all five pear genotypes examined. However, transcript abundance was increased in correlation with the presence of p-hydroxystyrene in resistant cultivars Py-701 and Py-760 and in the sensitive cultivar Spadona when grafted on these resistant cultivars. Thus, PyPAD1 appears to be responsible for the decarboxylation of the p-coumaric acid, and for the production of metabolites that are active against pear psylla.

Development of an integrated 200K SNP genotyping array and application for genetic mapping, genome assembly improvement and genome wide association studies in pear (Pyrus).

SummaryPear (Pyrus; 2n = 34), the third most important temperate fruit crop, has great nutritional and economic value. Despite the availability of many genomic resources in pear, it is challenging to genotype novel germplasm resources and breeding progeny in a timely and cost‐effective manner. Genotyping arrays can provide fast, efficient and high‐throughput genetic characterization of diverse germplasm, genetic mapping and breeding populations. We present here 200K AXIOM ® PyrSNP, a large‐scale single nucleotide polymorphism (SNP) genotyping array to facilitate genotyping of Pyrus species. A diverse panel of 113 re‐sequenced pear genotypes was used to discover SNPs to promote increased adoption of the array. A set of 188 diverse accessions and an F1 population of 98 individuals from ‘Cuiguan’ × ‘Starkrimson’ was genotyped with the array to assess its effectiveness. A large majority of SNPs (166 335 or 83%) are of high quality. The high density and uniform distribution of the array SNPs facilitated prediction of centromeric regions on 17 pear chromosomes, and significantly improved the genome assembly from 75.5% to 81.4% based on genetic mapping. Identification of a gene associated with flowering time and candidate genes linked to size of fruit core via genome wide association studies showed the usefulness of the array in pear genetic research. The newly developed high‐density SNP array presents an important tool for rapid and high‐throughput genotyping in pear for genetic map construction, QTL identification and genomic selection.

Evaluation of genetic variations and phylogeny of the most popular pear (Pyrus communis L.) cultivars in Duhok city using AFLP markers

Introduction: Genotyping and evaluation of genetic variation and polymorphic information content of the locally cultivated pear (Pyrus communis L.) might play an important role in building the genetic bank. These are also immensely important for present and future pear breeding program in the region. Methods: In the current study, AFLP markers have been employed to estimate the level of genetic diversity and to assess the phylogeny among theseven most popular pear cultivars in Duhok city. Results: Eight selective primer combinations generated a total of 653 AFLP fragments from which 445 (68.2%) fragments were polymorphic. The number of visible amplified products per primer combination were varied and ranged from 66 to 96 bands. The highestpercentage of polymorphism (78.4%) was observed by the primer pair P174/M182, while the lowest percentage of polymorphism (58.6%) was observed by the primer pair P174/M100. The highest PIC (0.85) was obtained with the primer combination P174/ M182, while, the lowest PIC (0.49) was obtained by the primer combination P174/M307. The genetic distance was ranged from 0.1348 (between Danimarki and Amreki cultivars) to 0.3131 (between Italy and Zaafaran2 cultivars). Based on the AFLP data, all the seven pear genotypes were successfully clustered into two separate clusters (C1 and C2) with an out-group of Itali cultivar. Conclusions: Overall, it can be concluded that there was high polymorphism among the studied genotypes. Also, it can be stated that the AFLP was a reliable and a powerful technique in genotyping and discriminating of respective pear cultivars.

Microsatellites as a tool for identifying successful pollinators of the pear cultivar ‘Ingeborg’ in Ullensvang, Norway

Due to their Mendelian inheritance, microsatellites or SSRs (simple sequence repeats) can readily be used for parentage analyses of pear seedlings, thus revealing the female and male parents of the plant. However, in cases where obtained pear seeds display low viability, conducting a parentage analyses on the pear seeds themselves could be used in order to identify the male parent (successful pollinator). In this study, batches of seeds were extracted from fruits of the triploid ‘Ingeborg’ pear (‘Conference’ × ‘Bonne Louise’), the main commercial pear cultivar in Norway. Mature pears were collected from eight commercial pear orchards located in Ullensvang, at 60° North and seeds were collected. Genomic DNA was subsequently isolated from the obtained seed batches and genotyped using 12 microsatellite markers. The same markers were also used for the genetic characterization of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards (‘Clara Frijs’, ‘Herzogine Elsa’, ‘Anna’, ‘Coloree de Juillet’ and ‘Belle lucrative’). The obtained SSR profiles were used in paternity analyses, as well as for gene assignment analyses. Both approaches identified pear ‘Clara Frijs’ to be the most successful pollinator in most of the sampled orchards. Subsequent S allele genotyping of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards revealed that the preferential pollination by individual genotypes was not caused by gametophytic incompatibility or semi-compatibility.