Changes in cell wall polysaccharides and cell wall degrading enzymes during ripening of Fragaria chiloensis and Fragaria ×ananassa fruits

Chilean strawberry (Fragaria chiloensis) is arising as a new fruit crop that can diversify the world supply of berries. Fruit softening is thought to be linked to an extensive modification of pectin and hemicellulosic cell wall fractions which in turn is determined to a great extent by the action of some cell wall-modifying enzymes. The objective of this work was to compare cell wall changes and the enzyme activities of pectin methylesterase (PME), polygalacturonase (PG), endoglucanase (EGase), α-arabinofuranosidase (AFase), β-galactosidase (βGal), and β-xylosidase (βXyl) between F. chiloensis and Fragaria ×ananassa (cv. Chandler) at three fruit developmental stages: large green (LG), turning (T) and ripe (R). A rapid decrease in fruit firmness between LG and T stages was observed in both species; nevertheless firmness reduction in F. chiloensis was steeper than in F. ×ananassa. This could be related to a faster loss of HCl-soluble polymers (HSP fraction) presented in F. chiloensis fruit. However, commercial F. ×ananassa showed a greater depolymerization of HSP polymers than F. chiloensis. With the exception of PME, the activity of all assayed enzymes was higher in F. chiloensis than in F. ×ananassa fruits. The role of PG and EGase seems to be central in both species: these enzymes are correlated to the decrease in the content of HSP and NaOH-soluble polymers (NSP fraction), respectively. In addition, activity levels of βGal and βXyl were significantly correlated with fruit firmness reduction in F. chiloensis and F. ×ananassa, respectively.     

Comparison of cell wall components between Fragaria × ananassa and Fragaria chiloensis grown in Chile

Summary

Fruit firmness and cell wall composition were compared among five cultivars of F. × ananassa (‘Chandler’, ‘Seascape’, ‘Tudla’, ‘Hokowase’ and ‘Reiko’) and two land races of F. chiloensis (‘94BAU-1A’ and ‘97PUR-1A’) grown in central Chile. Fruits of F. chiloensis were smaller than those of F. × ananassa. Firmness of epidermal tissue did not differ significantly between F. × ananassa and F. chiloensis. Firmness of cortical tissue, however, was significantly lower in F. chiloensis than in F.× ananassa and as a result, difference in the firmness between epidermal and cortical tissues was significantly greater in F. chiloensis than in F. × ananassa. Calcium concentration was low in ‘Reiko’ and ‘Hokowase’ while high in the other varieties of F. × ananassa. F. chiloensis showed intermediate values between these two groups. Higher levels of total uronic acid and neutral sugars in cell wall fractions of F. chiloensis as compared with F. × ananassa were mainly due to its high concentration in the water soluble fraction. Total uronic acid in cell wall fraction was significantly higher in F. chiloensis than in F. × ananassa, mainly due to significantly higher concentrations in the water-soluble fraction. Non-cellulosic neutral sugars, especially arabinose in the water, CDTA, and Na₂CO₃-soluble fractions were significantly higher in F. chiloensis than in F. × ananassa. On the other hand, galactose in the CDTA-, Na₂CO₃-, and KOH-soluble fractions was significantly lower in F. chiloensis than in F. × ananassa. Moreover, cellulose concentration of F. chiloensis was also significantly lower than that of F. × ananassa. Results obtained from cell wall analysis suggest that softer cortex in F. chiloensis might be due to either lower cellulose content, higher solubilization rate of pectic substances, and/or compositional differences in the branching of neutral sugars.     

The temperature and photoperiod regulation of flowering and runnering in the strawberries,Fragaria chiloensis,F. virginiana,and F. x ananassa

The temperature and photoperiod interactions of a number of elite genotypes of Fragaria virginiana, F. x ananassa, and F. chiloensis were studied in a series of growth chamber experiments. Several parameters were evaluated including: (1) the critical day-length (CDL) for flowering of short day (SD) genotypes under 8, 9, 10, and 11 h days at 18 °C, (2) the floral and runnering response of single and multiple cropping genotypes under 8 and 16 h days at 18 °C, and (3) the effect of temperature on flower bud formation in day-neutral (DN) genotypes held at 18, 22, 26, and 30 °C under 12 h day-lengths. The same number of flowers were initiated under 15 and 30 day induction periods, regardless of photoperiod. Frederick 9, LH 50-4 and RH 30 (F. virginiana), ‘Aromas’ and ‘Tribute’ (F. x ananassa) and CFRA 0368 of F. chiloensis flowered under both long days (LDs) and SDs; while Eagle-14 (F. virginiana), ‘Fort Laramie’ and ‘Quinalt’ (F. x ananassa) flowered only under long days. While those genotypes that flowered under both LD and SD can be considered day-neutral, they varied in the degree of floral response to the two photoperiods. CFRA 0368 and Frederick 9 produced the same number of flowers under both LDs and SDs, while ‘Aromas’ and ‘Tribute’ had more flowers under LDs and RH 30 had more under SDs. Of the DN genotypes, LH 50-4 and RH 30 were the only ones that produced runners under SDs. Flowering in ‘Fort Laramie’ was least affected of any genotype by high temperature, although its dry weight was negatively impacted. Based on these data, several genotypes show promise as breeding parents: CFRA 0368 and Frederick 9 to equalize flower production under LD and SD conditions, LH 50-4 and RH 30 to produce more freely runnering DNs, and ‘Fort Laramie’ for floral heat tolerance.     

Resistance to Botrytis cinerea in pistillate genotypes of the cultivated strawberry Fragaria ananassa

Four strawberry families which segregated for pistillate and hermaphrodite flowers were assessed for their susceptibility to Botrytis cinerea (grey mould). Clonally propagated plants were grown in a glasshouse and the flowers sprayed with a conidial suspension of the fungus. In extreme cases the disease resulted in necrosis of the flowers and pedicels before fruit development had begun. This occurred in a significantly higher proportion of hermaphrodite than pistillate flowers. Necrosis due to B. cinerea in unripe and ripe berries was also significantly greater in plants with hermaphrodite flowers. Differences in susceptibility between families were also observed, but there was no interaction with flower sex. It is proposed that the reduced incidence of necrosis on the flowers and fruit of pistillate plants is due primarily to the absence of anthers, which in hermaphrodite flowers.provide a major route for B. cinerea to enter the developing receptable.     

Flowering Tendencies in Octoploid Strawberry Species

ABSTRACT

The U.S. Department of Agriculture, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, maintains a national genebank for strawberry, Fragaria L. This collection includes diverse species maintained in screenhouses. The plants are exposed to an annual temperature regime that allows flowering. The objective of this project was to examine the flowering tendencies of octoploid strawberry taxa to determine if the blooms were seasonal (once per year) or successive blooming (remontant). For each of 68 clones of nine taxa, flower presence was recorded on the first day of each month from June through Oct. 2002 and in 2004. Complete flower trusses were removed after scoring. Plants flowering only in June and/or July (or earlier) were considered “seasonal”; those with later flowers were considered “successive blooming.” For both years, North American F. chiloensis ssp. lucida and ssp. pacifica flowered seasonally, significantly different than clones of ssp. chiloensis f. patagonica, half of which were successive blooming. A clone of ssp. pacifica from Hartney Bay, Alaska, was successive blooming. The flowering in two clones of South American ssp. chiloensis f. chiloensis and one of the Hawaiian ssp. sandwicensis were seasonal. Fragaria virginiana ssp. grayana clones and half of the ssp. virginiana Mill. flowered seasonally; the rest of the clones of those subspecies were successive blooming. Flowers of a clone of F. virginiana ssp. platypetala from California were seasonal while those from a second one from Eastern Oregon were successive blooming. This clonal phenotypic information is of specific use for geneticists to determine parental crosses. This study will be continued and broadened to include diverse global species.     

The Genus <Emphasis Type="Italic">Fragaria </Emphasis>in Croatia

Only three native species of genus Fragaria (F. moschata, F. vesca and F. viridis) are recorded in three regions of Croatia. These species as well as many of their hybrids, are, or once were, cultivated for their edible fruits. The majority of cultivated strawberries in Europe belong to garden strawberries F. x ananassa (hybrids of F. chiloensis and F. virginiana). The most expanded wild strawberry species in Croatia is a woodland strawberry (F. vesca) whose berries are gathered seasonally as wild edible fruits. They often contain higher amount of nutrients and bioactive compounds in comparison to cultivated varieties. The research on the genus Fragaria species distribution in Croatia has not been carried out, and so is the case with many others wild growing fruit species in Croatia. By summing up a number of individual citations and observations, it is possible to get a perspective regarding the current state of their distribution.     

First reported case of spontaneous hermaphrodism in female date palm (Phoenix dactylifera L.), cv ‘Alligue’

The date palm (Phoenix dactylifera L.) is dioecious with male flowers deficient in functional gynoecium and female flowers deficient in functional androecium borne on separate palms. The presence of male and female flowers on the same plant, a phenomenon known as monoecy, is unusual in male date palms.

This study reports for the first time on hermaphrodite (bisexual) flowers borne by two female date palms, ‘Alligue’, that were found growing in an open field in Degache, southern Tunisia. The observations on these two female palms were compared with hermaphrodite male date palms growing in the same location. Hermaphrodite female date palm inflorescence branches bear female flowers predominantly near their base, in contrast to the hermaphrodite flowers that are found primarily toward their upper part. The position of the hermaphrodite flowers in hermaphrodite male date palms is reversed: inflorescence branches bear male flowers toward the upper part while the hermaphrodite flowers are found at the base. Histological examination of female hermaphrodite flowers revealed that they had three carpels and 1–6 stamens. Hermaphrodite flowers on male plants were usually also composed of three carpels of variable size, and six stamens. Hermaphrodite flowers on both female and male palm trees turn generally into parthenocarpic fruits. The present data support the theory that dioecious plants are derived from a common hermaphrodite ancestor. Floral hermaphroditism in date palm should be investigated in relation to the in planta self-fertilization process to identify sex markers and genes that control sex organ development.     

A new set of microsatellite markers for Fragaria species and their application in linkage analysis

Summary

This study reports the development of 68 new microsatellite markers. Of these, 45 were obtained, together with 20 others already published, from an AC-enriched genomic library of the wild strawberry Fragaria vesca. The 68 markers were tested for transportability to the cultivated strawberry F. ananassa ‘Miss’ and 83% gave positive amplifications. Twenty pairs of primers were selected and tested for their transportability to 16 Fragaria taxa and eight species of Rosaceae (peach, almond, apricot, European and Sino-Japanese plums, sweet and sour cherry, apple). The average proportion of primers amplifying loci in Fragaria was 69%, while the transportability to Rosaceae was very low and resulted in null amplification for 80% of the primer pairs. In addition, 23 microsatellite markers were developed from F. ananassa ‘expressed sequence tags’ databases. A total of 141 primer pairs from these and published primers, were tested for polymorphism in the two parents (91.333.2 and ‘Snovit’; both belonging to F. vesca) of a full sib population of 46 individuals. Fifty-eight percent of the primers were discarded because they were monomorphic, or were difficult to interpret, or their allelic conformation was not useful for mapping. The segregation of 73 primers was tested in the progeny and a partial map of the female parent was constructed, based on the segregation of 66 useful markers that were ordered into eight linkage groups of which four had from seven to 14 markers.     

苦瓜第1雌花节位和雌花数的杂种优势

将8个绿苦瓜高世代自交系分为两组;共配制15个杂交组合,对第1雌花节位和主蔓前期雌花数的杂种优势进行了研究。结果表明:第1雌花节位有6个组合表现负向离中优势,有13个组合表现为负向越亲优势,且有4个组合低于小值亲本;雌花数有5个组合表现为正向离中优势,有4个组合表现为正向超亲优势。通过对第1雌花节位与雌花数两个性状亲子关系的讨论提出实现早熟性和晚熟性育种目标的亲本选配方法。     

Flower Sex Expression in Lychee (Litchi chinensisSonn.) Is Affected by Gibberellic Acid and Naphthalene Acetic Acid

ABSTRACT

Gibberellic acid (GA₃) at 25, 50, and 100 mg-L^?1 and naphthalene acetic acid (NAA) at 20, 40, and 80 mg-L^?1 were sprayed to runoff on flower panicles of 15-year-old lychee trees one week after panicle emergence. Trees sprayed with water only were used as the control. The number of male flowers was increased quadratically by NAA compared to the control in 2000, and 2001. The number of hermaphrodite flowers functioning as female (HF-F) and the number of hermaphrodite flowers functioning as male (HF-M) was reduced quadratically by all concentrations of NAA both years. The greater the NAA concentration, the greater the reduction. The total number of flowers was also reduced by all NAA concentrations both years. Fruit set (percentage of total HF-F flowers) was reduced quadratically by NAA in 2001, but had no effect in 2000. The number of male flowers was increased quadratically by GA₃ both years. Regression analysis also showed a positive relationship between GA₃ and HF-F flowers both years. However, hermaphrodite flowers functioning as male (HF-M) was reduced quadratically by GA₃ both years. In addition, the total number of flowers and fruit set was increased quadratically by GA₃ both years. GA₃promotion of male flowers, HF-F production, and increased fruit set may have important bearing on yield improvement.     

辣椒资源创新研究 Ⅰ辣椒F_2世代一些性状的分离及分布特性

以一个单交组合的F2世代为材料,研究了与辣椒高产、优质育种目标相关的4个性状的分离及分布特性。结果表明:果长的分离中出现超(大)亲分离的现象,而果宽、坐果数/株的分离中呈现超(小)亲分离的现象;果重、果长、果宽的表现型为正态分布,而坐果数/株的分布具有极显著的偏畸(P<0.01)。F2世代分离出的植株类型较为丰富,在这4个性状的表现上,有些植株和一代杂种F1类似,有些植株的比F1优良,还有植株的表现比母本优良。     

Studies on the Nutrition of Tulips and Narcissi

Summary

We explored the effects of pollination method (hand cross-, hand self-, automatic self-, and open-pollination) and pollen source on fruit set and growth in four red-skinned pitaya (Hylocereus spp.) cultivars [‘Vietnam White’ (‘VNWhite’), ‘Chaozhou 5’, ‘Orejona’, and ‘F11’] in Taiwan.‘VN-White’ has white flesh, while the other three cultivars have red flesh. There were no significant differences in pollen viability or germination rate among the four cultivars, irrespective of whether the pollen was collected at night (approx. 20.30 h) or on the following morning (approx. 08.30 h).The results also indicated that ‘VN White’ was fully self-compatible and exhibited a high fruit set percentage (80 - 96%) following all pollination treatments. This cultivar produced the largest fruit from both hand self- and openpollination, compared to the three other cultivars tested. ‘Chaozhou 5’ was partly self-compatible, and ‘Orejona’ and ‘F11’ were completely self-incompatible. Hand cross-pollination significantly increased the fruit set percentages and mean fruit fresh weights (FWs) in ‘Chaozhou 5’ and ‘Orejona’. Pollen source also significantly affected the fruit set percentage and fruit FW. ‘VN-White’ (after self-pollination) and ‘Chaozou 5’ (after crossing with ‘VN-White’) gave superior fruit set percentages and fruit FWs. Reciprocal crosses between ‘Orejona’ and ‘F11’ also resulted in high fruit set percentages as well as large fruit in both cultivars. Therefore, the source of pollen and the method of pollination can affect fruit production in some cultivars of pitaya. Self-compatibility in ‘VN-White’ concurs with the morphology of its flowers in which the anthers lie in close proximity to the stigma.The distance between the anthers and the stigma may be used an indicator of whether hand pollination is necessary for a pitaya cultivar.     

甜瓜不同性别花蕾发育中激素和多胺的变化

 以甜瓜雌雄异花同株和雄全同株近等基因系为材料，采用高效液相色谱(HPLC)技术，分析雌花、雄花和两性花4种内源激素和4种多胺含量的动态变化。结果显示，雌花和两性花发育初期和后期GA₃含量高于雄花；多数时期雄花ZT和IAA含量高于雌花和两性花；雄花发育中、后期 ABA含量较大幅度上升，且明显高于雌花，两性花ABA含量变化趋势与雌花相近，但整体明显高于雌花；ZT/GA₃比值雄花高于雌花和两性花。由此表明，较高的GA₃含量，较低的ZT和IAA含量有利于雌蕊的发育，较高的ABA含量有利于雄蕊中、后期的发育。花蕾发育初期，尸胺(Cad)含量从高到低依次为雌花、两性花和雄花，随着发育的进行，雄花和两性花中Cad含量呈现较大幅度上升，而雌花始终保持在相对较低的水平。因此，相对较高的Cad含量可能有利于早期雌蕊的发育，较低的Cad含量有利于雄蕊的发育，而后期则相反，高含量的Cad有利于雄蕊的成熟；高含量的Spd可能有利于早期雌蕊的发育。     

Agronomic,cytogenetic and molecular studies on hermaphroditism and self-compatibility in the Greek kiwifruit (Actinidia deliciosa) cultivar ‘Tsechelidis’

The development of hermaphrodite cultivars of kiwifruit (Actinidia deliciosa) to overcome dioecism is a priority for all breeding programmes, worldwide. If successful, the number of pollinators in the orchard could be reduced, allowing more space for reproductive vines. Hermaphroditism and the expression of self-compatibility were studied in A. deliciosa, using the new kiwifruit cultivar, ‘Tsechelidis’, as a model. This plant material was chosen for investigation as its female flowers produced viable pollen. The aim of the present study was to investigate the expression and nature of self-compatibility in ‘Tsechelidis’ and to evaluate its potential for breeding purposes. The expression of self-compatibility in ‘Tsechelidis’, between years, was investigated by controlled self-pollination of female flowers in the field and by microscopic studies on pollen viability in the laboratory. The commercial cultivar ‘Hayward’ and the pollinator ‘Matua’ were used as controls. Controlled self-pollination in the field confirmed that ‘Tsechelidis’ exhibited a degree of hermaphroditism and self-compatibility. Its flowers produced viable pollen and could set fruit of an acceptable size and quality after self-pollination, compared to open-pollinated fruit. The average fruit set percentage for ‘Tsechelidis’ was 34%, and ranked from 20% to 60% per vine, while the corresponding rate for ‘Hayward’ was only 4%. Microscopic studies on ‘Tsechelidis’ pollen revealed variations in pollen viability between different vines, which were even greater between different flowers on the same vine, ranging, in some cases, from 0% (absolutely sterile) to 70% (significantly fertile) per flower. Female control ‘Hayward’ vines were found to be practically sterile (0%), while male control ‘Matua’ vines were almost 100% fertile. The nature of self-compatibility in ‘Tsechelidis’ was investigated further by molecular analysis using the sex-linked sequence characterised amplified region (SCAR) markers, SmX, SmY, and SmY1, and by single nucleotide polymorphism (SNP) analysis. Hermaphroditism in ‘Tsechelidis’ was related to sex expression, as observed by SNP analysis, but complete genome mapping would be required to fully understand the mechanisms involved and to exploit this new genetic material for breeding purposes.     

Microsatellite markers reveal low breeding system efficacy and pollen contamination can limit production of full-sib avocado progeny

Phytophthora cinnamomi causes a severe root rot in avocado, Persea americana. Breeding tolerant rootstocks is thought to be the most promising method for phytophthora root rot disease control but breeding avocado is challenging. The avocado flowering syndrome (synchronous protogynous dichogamy), combined with high flowering and low fruit set, render controlled pollination exceedingly difficult. Juxtaposing complementary flowering types of elite parent cultivars (cultivars that produce progeny with tolerance to phytophthora root rot) was performed in an effort to increase the number of full-sib progeny for elite maternal parents and, hypothetically, the number of phytophthora root rot tolerant progeny. Although high outcrossing rates were achieved (estimated ∼93%), the majority of progeny had a non-elite paternal parent (56% of progeny were offtypes) implying maternal trees were pollinated by non-elite distant trees. Among progeny that could be confidently genotyped, a high number of cross types were detected (33). Contrary to our hypothesis, a significant portion of the progeny were the result of crosses between like, and not complementary, flowering types. The spatial distribution of productive trees and grafts helped to explain these data, as productive grafts were directly adjacent to grafts of the same flowering type more often than that of the complementary flowering type. Selfed progeny were significantly less tolerant to phytophthora root rot than outcrossed progeny. Progeny resulting from crosses between an elite maternal parent and non-elite pollen donor (offtypes) were less tolerant than full-sib progeny resulting from crosses between elite parents. Maternal effects may interfere with identifying truly disease tolerant selections. Thus, to reduce maternal effects and non-elite pollen donor contamination, removal of seedling cotyledons before screening for disease tolerance and better isolation of elite parent trees and windbreaks may improve breeding efficacy. This study also demonstrates the usefulness of microsatellite markers in parentage analysis where a high proportion of the putative parents are closely related.     

Initiation and development of pistillate flowers in Actinidia chinensis

Initiation and development of pistillate flowers in Actinidia chinensis Planch, cultivar ‘Hayward’ (kiwifruit, Chinese gooseberry) was followed using light and scanning electron microscopy. Results indicate that dormant buds contain undifferentiated primordia in the leaf axils. These primordia remain undifferentiated until shortly before bud break, approximately two months before full bloom, when the primordia become trilobed as bracts and lateral flower primordia are initiated. The lateral flowers often abort in this cultivar. Acropetal development of the terminal flower proceeds rapidly. Five to seven sepals are initiated, followed by a whorl of five to seven petals. Stamen initiation is centripetal and the anthers develop to produce inviable pollen. The central portion of the floral apex is converted into a large compound pistil with numerous hollow styles, each terminated by an open stigma.     

耐贮运厚皮甜瓜新品种酒研蜜1号的选育

酒研蜜1号是以B72为母本、MB3133为父本选育而成的中熟厚皮甜瓜杂交1代新品种.该品种在酒泉地区春季露地直播栽培条件下,全生育期88 d左右,果实发育期40 d,单果质量2.0～2.3 kg,667 m2产量3200 kg左右;果实短椭圆形,果形指数为1.1,雌花为两性花,易坐果,果皮色为白色,成熟时表皮略微泛黄,...     

Autotetraploid Green Watercress

Auxin-phloroglucinol synergism has been observed to promote the rooting of the Rubus hybrid (R. ursinus Cham, and Schlectxß. idaeus L.) but not the perpetually fruiting strawberry cv Gento Hummell (a hybrid of Fragaria virginiana Duchesne xF. chiloensis Duchesne). In strawberry PG was successfully substituted for IBA but the presence of both IBA and PG reduced rooting compared with other treatments. In strawberry PG affected the organization of tissues and the pattern of root branching; no callus was formed and growth of second order laterals was enhanced. Promotive effects of PG on leaf development were observed in both species but their effects may be indirect since root development was enhanced in treatments that also stimulated leaf growth. In both Rubus and strawberry the non-indole auxin a α-naphthaleneacetic acid showed no synergistic effects with PG on leaf and root development. These results demonstrate that the growth promotive effects of PG are not specific to Malus species.     

Evaluation of Strawberry Genotypes for Chaetosiphon fragaefolii (Strawberry Aphid) Preference

ABSTRACT

Thirty-one strawberry genotypes were evaluated for supporting the reproductive success of the strawberry aphid (Chaetosiphon fragaefolii), a vector of several strawberry viruses. A pure colony of C. fragaefolii was initiated from eggs collected from field strawberry leaves in Fall 2013. In Spring 2014 greenhouse-grown strawberry plants with four to five leaves were placed in screened cages (16 genotypes/cage) and five aphids were placed on each plant. After 30–32 days, the number of aphids in each of four developmental stages was counted on each plant. Total aphid numbers/plant ranged from a mean of 33 on Fragaria chiloensis CFRA 48 (PI 551459) to 279 on F. × ananassa ‘AAC Lila’. Cultivars with relatively low numbers of aphids included ‘Bounty’ (106 aphids), ‘Mira’ (114 aphids), and ‘Annapolis’ (115 aphids). This experiment, part of a larger project on aphids and virus diseases associated with the cultivated strawberry, will inform decisions in the strawberry breeding program.     

西葫芦新品种晋西葫芦4号的选育

西葫芦新品种晋西葫芦4号是以国外西葫芦品种的分离后代经多代自交选育而成的纯合自交系D-95-2为母本,以从我国地方品种白皮西葫芦中选育的稳定自交系E-96-8为父本杂交育成的早熟一代杂交种。该品种属短蔓密植类型,极早熟;嫩瓜皮色为鲜嫩的浅绿色,带细网纹,长筒形,光泽度好;植株生长势强,雌花多,瓜码密,耐低温、弱光,丰产,抗病,667m2产量5000kg左右。适合我国北方大部分地区早春各种保护地及露地栽培。