Loquat Varieties Research Articles

Comparative Study of New Loquat Varieties: Physico-chemical and Phytochemical Analyses

The present work performs a comparative study of 10 different loquat varieties to identify significant differences among varieties and categorize them based on their main physicochemical and phytochemical properties. For each variety, physicochemical properties (external and internal color, flesh firmness, soluble tannins, total soluble solids, titratable acidity) and the main phytochemical compounds (sugars, organic acids, vitamin C, phenolic compounds, carotenoids) were evaluated in fruit harvested at two commercial maturity stages. This study revealed significant differences in these characteristics among cultivars. Principal component analysis (PCA) allowed varieties to be grouped into three well-differentiated groups, especially in terms of total acidity, phenolic compounds and carotenoids. PCA also allow fruit quality attributes to be correlated with the main bioactive compounds and clearly separated the maturity stages for each cultivar. These results reveal the diversity of chemical composition and nutritional value of loquat fruits and provide valuable information on the commercial potential of new varieties. Moreover, this information is valuable for breeding programs, as cultivars with specific traits can be used as parent material for future crosses.

Low Female Gametophyte Fertility Contributes to the Low Seed Formation of the Diploid Loquat [Eriobotrya Japonica (Thunb.) Lindl.] Line H30-6.

Loquat is a widely grown subtropic fruit because of its unique ripening season, nutrient content, and smooth texture of its fruits. However, loquat is not well-received because the fruits contain many large seeds. Therefore, the development of seedless or few-seed loquat varieties is the main objective of loquat breeding. Polyploidization is an effective approach for few-seed loquat breeding, but the resource is rare. The few-seed loquat line H30-6 was derived from a seedy variety. Additionally, H30-6 was systematically studied for its fruit characteristics, gamete fertility, pollen mother cell (PMC) meiosis, stigma receptivity, in situ pollen germination, fruit set, and karyotype. The results were as follows. (1) H30-6 produced only 1.54 seeds per fruit and the fruit edible rate was 70.77%. The fruit setting rate was 14.44% under open pollination, and the other qualities were equivalent to those of two other seedy varieties. (2) The in vitro pollen germination rate was only 4.04 and 77.46% of the H30-6 embryo sacs were abnormal. Stigma receptivity and self-compatibility in H30-6 were verified by in situ pollen germination and artificial pollination. Furthermore, the seed numbers in the fruits of H30-6 did not significantly differ among any of the pollination treatments (from 1.59 ±0.14 to 2 ± 0.17). (3) The chromosome configuration at meiotic diakinesis of H30-6 was 6.87I + 9.99II + 1.07III +0.69IV +0.24V (H30-6), and a total of 89.55% of H30-6 PMCs presented univalent chromosomes. Furthermore, chromosome lagging was the main abnormal phenomenon. Karyotype analysis showed that chromosomes of H30-6 had no recognizable karyotype abnormalities leading to unusual synapsis on the large scale above. (4) The abnormal embryo sacs of H30-6 could be divided into three main types: those remaining in the tetrad stage (13.38%), those remaining in the binucleate embryo sac stage (1.41%), and those without embryo sacs (52.82%). Therefore, we conclude that the loquat line H30-6 is a potential few-seed loquat resource. The diploid loquat line H30-6 was with low gametophyte fertility, which may be driven by abnormal meiotic synapses. The low female gamete fertility was the main reason for the few seeds. This diploid loquat line provides a new possibility for breeding a few-seed loquat at the diploid level.

Genotyping of polyploid plants using quantitative PCR: application in the breeding of white-fleshed triploid loquats (Eriobotrya japonica)

BackgroundPloidy manipulation is effective in seedless loquat breeding, in which flesh color is a key agronomic and economic trait. Few techniques are currently available for detecting the genotypes of polyploids in plants, but this ability is essential for most genetic research and molecular breeding.ResultsWe developed a system for genotyping by quantitative PCR (qPCR) that allowed flesh color genotyping in multiple tetraploid and triploid loquat varieties (lines). The analysis of 13 different ratios of DNA mixtures between two homozygous diploids (AA and aa) showed that the proportion of allele A has a high correlation (R2 = 0.9992) with parameter b [b = a1/(a1 + a2)], which is derived from the two normalized allele signals (a1 and a2) provided by qPCR. Cluster analysis and variance analysis from simulating triploid and tetraploid hybrids provided completely correct allelic configurations. Four genotypes (AAA, AAa, Aaa, aaa) were found in triploid loquats, and four (AAAA, AAAa, AAaa, Aaaa; absence of aaaa homozygotes) were found in tetraploid loquats. DNA markers analysis showed that the segregation of flesh color in all F1 hybrids conformed to Mendel's law. When tetraploid B431 was the female parent, more white-fleshed triploids occurred among the progeny.ConclusionsqPCR can detect the flesh color genotypes of loquat polyploids and provides an alternative method for analyzing polyploid genotype and breeding, dose effects and allele-specific expression.

EjFWLs are repressors of cell division during early fruit morphogenesis of loquat

Fruit size varies widely among different loquat species and varieties. While the cell number of fruit is considered as one of the main factors which affect fruit size forming of loquat, the mechanism of variation in fruit size of loquat is still poorly understood. In this work, we aimed to illuminate the functions of EjFWLs in fruit size forming of loquat. Two FWL (tomato FW2.2-like) genes, EjFWL1 and EjFWL2, of loquat were isolated and characterized. Expression analysis showed that transcription levels of both EjFWL1 and EjFWL2 are negatively correlated with that of EjCDKB1;2 in receptacle before bloom. Meanwhile, compared with that in small-fruited loquat varieties, expression of EjFWL1/2 in large-fruited loquat showed a lower level and shorter duration. Ectopic expression of EjFWL1 in tomato inhibited the fruit cell division with reduced ovary and fruit size. Moreover, EjFWLs could interact with EjAGL2 and EjCKIIβ, the proteins which may be involved in the regulation of cell division, respectively. Our data suggested that EjFWLs are cell division repressors and function during early stage of fruit enlargement in loquat.

An allotriploid hybrid developed from a female 2n gamete was obtained from Eriobotrya japonica (Thunb.) Lindl × E. deflexa (Hemsl.) Nakai

A triploid was obtained from loquat (Eriobotrya japonica cv. ‘Ninghaibai’) (2n = 2x = 34) × bronze loquat (Eriobotrya deflexa, 2n = 2x = 34). The leaves of the triploid had no petioles, similar to the female parent, and its stipules were obvious and dark green, similar to those of the male parent. There were signals of male parent DNA on ten chromosomes of the triploid according to genomic in situ hybridization (GISH) when DNA of bronze loquat was used as probe; the diploid hybrid also had ten chromosomes with signals of male parent DNA. All five selected simple sequence repeats (SSR) primers amplified specific loci of both parents. In particular, primer CH04c06 amplified both specific loci of the female parent but only amplified one specific locus of the male parent. The results of GISH and SSR marker analysis indicated that the 2n gamete which formed the triploid was from first-division restitution or pre-meiotic doubling of the female parent cv. ‘Ninghaibai’. The allotriploid can be used to breed seedless loquat germplasm with different flowering times from loquat directly or to breed new germplasm containing a few genomic components from bronze loquat, such as monosomic alien addition lines, monosomic alien substitution lines, and introgression lines. This is the first report of allotriploid in the genus Eriobotrya and it will provide a basis for breeding new loquat germplasms by distant hybridization and provide an ideal material for breeding new loquat varieties with different flowering time or time to maturity.

Isolation and Comparison of Eight SWEET17 Genes from Six Loquat Cultivars

The plant SWEET (Sugars Will Eventually be Exported Transporters) proteins, as newly discovered sugar transporters, play various important roles during plant depending on the transmembrane gradient of sugar concentration. SWEET17 protein is one of the SWEET family members transporting fructose in particular. In this study, we identified eight SWEET17s from six loquats (Eriobotrya japonica (Thunb.) Lindl.) cultivars and named them as Ej_NHB_SWEET17, Ej_BL_SWEET17a, Ej_ZH_SWEET17, Ej_MM-_SWEET17a, Ej_MM_SWEET17b, Ej_BL_SWEET17b, Ej_GY_SWEET17 and Ep_LY_SWEET17. All of the eight loquat SWEET17s have five to six transmembrane structures. Phylogenetic analysis indicated that Ej_NHB_SWEET17 had the farthest genetic relationship with other seven loquat SWEET17s, indicating that ‘Ninghaibai’ cultivar was far away from the other five loquat varieties possibly. The similarities of nucleotide and amino acid sequences between Ej_NHB_SWEET17 and the other loquat SWEET17s were only about 61 and 46%, respectively, while that among other seven SWEET17s were greater than 90%. The expression levels of loquat SWEET17s in leaves were positively correlated with the content of fructose, sorbitol and total sugar in various fruit from the six cultivars, in which the sugar contents in fruits of different cultivars varied significantly, that was probably related to expression levels of loquat SWEET17. Our results indicated that the expression level of loquat SWEET17s was probably related to the regulation of sugar contents of mature fruit, experimental confirmation needs to be performed. Together, these results indicated that EjSWEET17s possibly played important roles in the sugar accumulation of fruit, which could serve as the basis for further functional identification of such genes.

Endogenous phytohormones and the expression of flowering genes synergistically induce flowering in loquat

Flowering is an important process for the reproduction of higher plants. Up to this point, the studies on flowering have mostly focused on the model plant Arabidopsis thaliana, and the flowering mechanism of fruit trees remains mostly unknown. The diversity of the flowering time of loquat (Eriobotrya japonica Lindl.) makes it an ideal material to study the regulation of flowering. In this study, we first observed the inflorescence bud differentiation in two varieties of loquat that had different blooming times (cv. Dawuxing (E. japonica), that blooms in the fall and cv. Chunhua (E. japonica×Eriobotrya bengalensis Hook. f.) that blooms in the spring) and found that the starting time of inflorescence bud differentiation and the speed of inflorescence development were responsible for the difference in blooming times. The determination of endogenous phytohormones by high performance liquid chromatography (HPLC) indicated that abscisic acid (ABA), zeatin (ZT), and gibberellin (GA3) promoted flowering in loquat, while indole-3-acetic acid (IAA) was mainly involved in inflorescence bud differentiation in Chunhua. A transcription level analysis illustrated that multiple flowering-related genes could respond to different signals, integrate to the TFL1, AP1 and FT genes, and then synergistically regulate flowering in loquat. Thus, this study provides a new insight into flowering regulation mechanisms in loquat.

Characterization of volatiles in red- and white-fleshed loquat (Eriobotrya japonica) fruits by electronic nose and headspace solid-phase microextraction with gas chromatography-mass spectrometry

Abstract Aroma differences are generally sensed in white- and red-fleshed loquats. Here, volatile compounds in four white- and three red-fleshed loquat varieties were investigated by headspace solid-phase microextraction and combined analysis of electronic nose (e-nose) and gas chromatography-mass spectrometry (GC-MS). In total, 83 volatile compounds were identified, and 33 were common in all of the cultivars. D-limonene, hexanal, (E)-2-hexenal, octanal and nonanal were the most abundant volatile compounds. β-cyclocitral and β-ionone were only detected in red-fleshed varieties. Furthermore, Huayu Seedless 1 (triploid white-fleshed loquats) with low levels of terpenoid compounds detected by GC-MS were clearly differentiated from the other cultivars tested by principal component analysis (PCA), which was consistent with the e-nose results. PCA analysis showed that Huabai 1(white flesh cultivar)had a prominent volatile profile characterized by higher concentrations of C6 aldehydes and alcohols, (E)-2-hexanal, (Z)-3-hexenal and hexanal, (Z)-3-hexenol, (E)-2-hexenol and hexanol. In comparison with red-fleshed loquats, white-fleshed loquats were characterized by high aldehydes content. These volatile compounds served to recognize and classify all of the analysed varieties.

Postharvest regulated deficit irrigation in early- and intermediate-maturing loquat trees

Postharvest deficit irrigation (DI) strategies have been proven to advance bloom, harvest dates and economic return in loquat ‘Algerie’ trees because an early harvest results in higher loquat fruit prices. This fact poses the question of whether postharvest DI strategies could have a similar effect on more precocious cultivars than cv. Algerie, providing thus a more profitable option to farmers. In this work, the response of an early- and intermediate-maturing loquat cultivars (cv. Cardona and Algerie, respectively) to a summer early (DIearly) and late (DIlate) DI strategy was assessed in two parallel studies during three consecutive years. The effects of the DIearly and DIlate strategies on bloom date, percentage of fruit picked at harvest per picking date and yield of both loquat varieties were studied. Moreover, fruit quality of cv. Cardona at harvest was also assessed. Plant water status was monitored by midday stem water potential (Ψstem) measurements. Results showed that DIearly and DIlate strategies advanced bloom in both cultivars although a higher effect was observed with the DIearly than with the DIlate treatment. Water restrictions did not increase the percentage of fruit picked at any of the picking dates and did not affect yield or fruit quality in the early-maturing cultivar. In ‘Algerie’ trees, a higher percentage of fruit was generally picked during the first picking dates in the DIearly and DIlate treatments than in the control although differences were only statistically significant during the last experimental season. Yield was significantly higher in ‘Algerie’ DIlate trees than in control or DIearly trees two out of the three experimental seasons. Overall, results showed that the DIearly and DIlate strategies tested here did advance bloom in the early-maturing cultivar but did not have an effect on the percentage of fruit picked per picking date at harvest. Nevertheless, the fact that substantial water savings (>30%) were obtained with no detrimental effect on yield presents the use of postharvest DI strategies as an interesting option to be followed in early-maturing cultivars for a more efficient crop production.

Addition of straw from hyperaccumulator plants to cadmium-contaminated soil increases cadmium uptake by loquat seedlings.

The straw from three different cadmium (Cd) hyperaccumulators (Galinsoga parviflora, Youngia erythrocarpa, and Solanum photeinocarpum) was added to Cd-contaminated soil, and its effects on plant growth and Cd accumulation in loquat seedlings were evaluated. Straw from each of G. parviflora, Y. erythrocarpa, and S. photeinocarpum was added to Cd-contaminated soil before planting seedlings of two varieties of loquat (Dawuxing and Chuanzao). Addition of straw from G. parviflora and S. photeinocarpum increased the root and shoot biomasses of both loquat varieties, compared with that in the control. Addition of straw also increased Cd uptake by loquat seedlings. The treatments could be ranked, from highest Cd contents in roots and shoots of loquat seedlings to lowest, as follows: S. photeinocarpum straw>Y. erythrocarpa straw>G. parviflora straw>control. All three types of hyperaccumulator straw increased the amount of Cd extracted by shoots of two loquat seedlings, with the maximum effect in the S. photeinocarpum straw treatment. Addition of hyperaccumulator straw also resulted in increased soil invertase, urease, and catalase activities to varying degrees. Among the three types of hyperaccumulator straw, S. photeinocarpum straw was the most effective to increase Cd accumulation in loquat seedlings. Therefore, this material has the potential to increase the phytoremediation capacity of loquat seedlings in Cd-contaminated orchards.

Evaluation and comparative performance of six loquat (Eriobotrya japonica Lindl.) varieties under Punjab conditions

Evaluation and comparative performance of six loquat Eriobotrya japonica Lindl. cultivars viz. selections, pathankot, tanaka, golden yellow, pale yellow and improved golden yellow was studied under Punjab conditions in 2012-13 and 2013-14. The main objective of the study was to evaluate and recommend the loquat variety with higher yield potential and better fruit quality for the growers of Punjab. Among the six varieties of loquat, cv. Tanaka was found most promising on the basis of the maximum fruit weight (23.5g), fruits per cluster (12), fruit length (4.5cm) fruit breadth (3.64 cm) Pulp weight (29.52g) fruit yield (34.0g),TSS (11.03%.) with minimum acidity (1.12%), seed weight and seed number. Moreover ‘Tanaka’ fruits had higher consumer acceptance (7.83 out of 9) as compared to other loquat varieties under comparison. These varieties were compared with recommended varieties as standard check. The study indicate that cv Tanaka has the potential to excel under Punjab conditions as compared with the prior existing cultivation.

Colchicine-induced polyploidy in loquat (Eriobotrya japonica (Thunb.) Lindl.)

The induction of polyploids in loquat (Eriobotrya japonica (Thunb.) Lindl.) is of great interest for producing larger and seedless fruits according to market demands. Under this premise, this work was aimed to obtain tetraploid plants of loquat using the antimitotic agent colchicine. Experiments consisted in applying colchicine on shoot apex from in vitro-grown plants, in vitro-grown whole plants and ungerminated seeds. Treatments on the shoot apex or submerging whole plants produced no stable polyploids. Conversely, subjecting ungerminated seeds to colchicine produced two triploids in the 0.5 % (w/v) solution after 24 h and one tetraploid after 48 h. The triploids obtained among treated seeds make us believe that these plants were present in the hybrids original seedlot. Polyploidy levels were firstly detected by flow cytometry and later confirmed by chromosome counting and morphological characteristics. The relative fluorescence was 1.5-fold higher in triploids and twofold higher in tetraploids as compared to diploids. As expected, the chromosome number was 2n = 34 in diploids, 2n = 51 in triploids and 2n = 68 in the tetraploid. Moreover, differences in morphological characteristics between diploid and polyploid plants were significant. The tetraploid plant was more compact than triploids or diploids. Particularly, stomata of polyploids were larger with lower density than diploids. Results indicate that induction of polyploidy in loquat species is a reliable tool for breeding new loquat varieties.

Genetic diversity and relationships among 47 loquat varieties revealed by EST-SSR markers

The genetic diversity and relationships of 47 loquat varieties sourced from different geographic locations were studied by using EST-SSR markers derived from apple. Results show that 33 pairs of apple EST-SSR primers had clear amplification products in loquat cultivars, with a comparatively high transferability rate of 67.3% in loquat, among which 22 pairs of primers could amplify polymorphic PCR products. Otherwise, among the 29 recovered fragments, 80% of the PCR products contained the SSR markers. The genetic relationships of all the 47 loquat accessions were analyzed by using polymorphic EST-SSR markers, showing that these markers could clearly separate loquat samples. Based on the cluster analysis, all the loquat varieties clustered into two groups with accessions from China and Spain respectively. The clusters obtained agree with the origins of the cultivars. This study confirms that the EST-SSR markers from apple are suitable for studying genetic diversity among loquat varieties. The polymorphic markers obtained will be used for loquat genotyping in further studies.

Cultivar Differentiation Identified by SSR markers and the Application for Polyploid Loquat Plants

Here we established a DNA marker-based method to identify cultivars of loquat (Eriobotrya japonica Lindl.) using simple sequence repeat (SSR) markers derived from pears and apples. A total of 24 loquat cultivars commercially grown in Japan were used for genetic identification, including 15 diploid-, 6 triploid-, and 3 tetraploid cultivars. Analysis using the 88 SSR markers derived from pears and apples, which belong to the same subfamily (family Rosaceae, subfamily Maloideae) as the loquat, indicated that 26 SSR markers were applicable to the identification of loquat cultivars. A total of 82 putative SSR alleles were obtained by the 26 SSR markers. SSR analysis enabled the identification of all loquat varieties tested, except for ‘Tomihusa’ and ‘4N-Tomihusa’. In addition, the parentages of several cultivars, including ‘Oohusa’ and ‘Mizuho’, were confirmed from the SSR genotype data obtained. Triploid and tetraploid varieties could be identified from the SSR genotypes because some SSR loci generated 2 or more alleles for polyploids. The relationship between ‘Kibou’ and its parents was confirmed since SSR alleles of the seedless triploid offspring ‘Kibou’ were clearly inherited from the female parent ‘4N-Tanaka 1’ and the male parent ‘Nagasakiwase’. The phenogram obtained by cluster analysis showed no distinctive separation of Japanese commercial cultivars from Chinese cultivars. This result was consistent with the hypothesis that Japanese commercial cultivars were derived from introduced Chinese loquat.

Capacidade de enraizamento de variedades de nespereira submetidas à poda de renovação

O presente trabalho avaliou a capacidade de enraizamento de cinco variedades de nespereira (Eriobotrya japonica Lindl.), sendo Champagne, Precoce de Itaquera, Mizuho, Mogui e Tanaka, obtidas pela poda de renovação. Estacas tenras apicais, contendo um par de folhas e cerca de 15 cm, foram tratadas por cinco segundos com ácido indolbutírico (IBA) (0; 1.000; 3.000; 5.000 e 7.000 mg.L-1). O experimento foi conduzido em câmara de nebulização intermitente pertencente à UNESP/FCAV (21º15'22" S e 48º18'58" W). O delineamento experimental foi inteiramente casualizado, em esquema fatorial 5x5 (5 variedades e 5 concentrações de IBA), com 4 repetições e 10 estacas por parcela. As avaliações foram feitas após 90 dias. Os resultados indicaram um incremento de enraizamento e número de raízes crescente com a concentração de IBA utilizada, com exceção da variedade Mogui, que apresentou melhores resultados apenas quanto ao comprimento de raízes. Posterior ao transplantio, a sobrevivência das mudas foi alta (90%), apresentando condições de serem plantadas no campo, aos seis meses, ou de serem enxertadas aos oito meses, decorrido desde o estaqueamento.

ビワのファイトアレキシンとがんしゅ病菌の系統および品種との関係

ビワのファイトアレキシンとがんしゅ病菌の系統および品種との関係

Effects of Gibberellic Acid on Loquat (Eriobotrya JaponicaLindl.)

In experiments on two varieties of loquat the spray application of gibberellic acid at 300 p.p.m. to flowering branches resulted in materially increased fruit set and retention. The fruits on the treated branches were seedless and were smaller and more elongated than the seeded fruits on untreated branches.