Some observations on the influence of temperature on the germination of pollen on excised nashi (<i>Pyrus serotina</i>Rehder var.<i>culta</i>Rehder) flowers

Rohitha, B. H.; Klinac, D. J.

doi:10.1080/01140671.1994.9513843

Cited by 8 publications

(4 citation statements)

References 10 publications

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“…Pollen tube growth in the pistil was much faster in 2018 compared to 2017 due to higher temperatures during the flowering stage. The obtained results clearly indicated a specific response of each genotype in relation to temperature variations [26], which is already proved for other pear cultivars [17,45,46]. The temperature during the reproductive phase could act as a selective pressure agent for genotypes that are better adapted to warm climates [47].…”

Section: Pollen Tube Growth In Pistilssupporting

confidence: 68%

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

2020

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Norwegian pear production is low due to climatic limitations, a lack of well-adapted cultivars and suitable pollinizers. However, nowadays it is increasing as a result of newly introduced and bred pear cultivars. Since cross pollination is necessary for high yields and good fruit quality, the aim of this investigation was to find the most suitable pollinizers for the pear cultivars “Ingeborg” (“Conference” × “Bonne Louise”) and “Celina” (“Colorée de Juillet” × “Williams”). Self-pollination of “Ingeborg” and “Celina”, together with “Conference”, “Belle Lucrative”, “Anna”, “Clara Frijs”, “Herzogin Elsa”, “Kristina” and “Fritjof” as potential pollinizers, were studied in this experiment during the 2017 and 2018 seasons in Norway. The success rate of each pollinizer was tested under field conditions, while the monitoring of pollen tube growth was done using the fluorescence microscopy method. All reproductive parameters (pollen germination, number of pollen tubes in the upper part of the style, pollen tube number in the locule of the ovary, number of fertilized ovules, initial fruit set, and final fruit set) in all crossing combinations were higher in 2018 due to much warmer weather. Based on the flowering overlap and success rate of each individual pollinizer and fruit set, the cultivars “Anna” and “Clara Frijs” can be suggested as pollinizers for the cultivar “Ingeborg”, while “Fritjof”, “Anna”, “Kristina” and “Herzogin Elsa” for the cultivar “Celina”. An even distribution of two compatible pollinizers having overlapping flowering times with the main commercial pear cultivar is a general recommendation for commercial pear production.

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Section: Pollen Tube Growth In Pistilssupporting

confidence: 68%

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

2020

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“…Few studies have dealt with the morphology and viability of pollen from the Thai cultivars. Low-temperature inhibition of pollen viability and pollen tube growth has also been reported for cultivars of other tree species including avocado (Sedgley and Annells, 1981;Sedgley and Grant, 1983), nashi (Rohitha and Klinac, 1994) and mango (Robbertse et al, 1988;Issarakraisila and Considine, 1994;Sukhvibul et al, 2000). Their results show that the specific temperature requirements for in vitro pollen germination of mango varied between cultivars.…”

Section: Introductionmentioning

confidence: 62%

Morphology and Factors Affecting Germination of Litchi Pollen

Sukhvibul¹,

Dasananda²

2014

Acta Hortic.

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Pollen morphology and factors affecting in vitro pollen germination of four commercial litchi cultivars, Hong Huay, O Hia, Kim Cheng and Jakapad, were studied at Chiang Rai Horticultural Research Center, Thailand. The pollen was germinated in liquid medium by using a hanging drop technique in the controlled temperature incubator. The litchi pollen was oblong when dehiscenced, becoming triangular or sometimes rectangular after germination in the liquid medium. The pollen was binucleate and an average length was 27-28 m depending on cultivars. There was no difference in germination percentage of 'Hong Huay' pollen incubated in either the presence of light or the darkness at 25C for 24 hours. There was no significant difference in pollen germination between 'Hong Huay' and 'Jakapad' at any incubation periods in the dark at 25C for 3-24 hours. Average germination percentage of both cultivars sharply increased to 69.2% when the incubation period was prolonged to 3-12 hours. Extending the duration of incubation beyond 18 and 24 hours, germination slowly increased to 87.4 and 89.0%, respectively. In this study, as temperatures increased there was a trend for the pollen germination of all cultivars to increase. Averaged over the four cultivars, 2.0% of pollen germinated at 10C, this increased to 14.7, 49.6, 60.1 and 63.9% when the incubation temperature was increased to 15, 20, 25 and 30C, respectively. Raising the incubation temperature to 35C resulted in decreased germination to 59.8%. The best temperature of pollen germination for all four litchi cultivars was between 25 and 35C.

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“…Rohitha and Klinac [33] listed several factors that can influence pollination, fruit set and yield in apple and pear cultivars, including distance from the polliniser and pollen availability, plant nitrogen status, water on the stigmas and the overlapping of flowering between compatible cultivars. Yoneyama [30] also noted that pollen attachment is reduced when the sigma is dry and advised that strong, dry winds can prevent full expansion of nashi flowers, leading to loss of viability.…”

Section: Fruit Setmentioning

confidence: 99%

Crop Load Management in Nashi Pear—A Review

Bound

2022

Horticulturae

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Most nashi cultivars require heavy thinning, and this has traditionally been performed by the time and labour-intensive practice of hand thinning. Crop load management is a key cost driver for nashi production, but there are limited cost-effective options available for nashi growers compared to other pome fruit, especially apples and, to a lesser extent, European pears. There is, however, potential to adapt some of the thinning tools and techniques used in apples and European pears to reduce the labour requirements and high cost of thinning in nashi, thus improving industry profitability. Several chemical thinning agents have potential for nashi, and an understanding of the optimal application rates, times and weather conditions for each chemical, as well as the conditions/factors that impact the tree carbon balance, will improve the predictability of chemical thinning. However, it is difficult to target specific flowers/fruitlets within a cluster with chemicals, and the flowers that produce the preferred fruit shape and size are in the middle of the flower cluster. Mechanical thinning during the flowering period with either Darwin or BAUM-style string thinners has potential, particularly as these devices can be used as early as flower emergence. As for chemical thinning, the issue of non-selectivity needs to be addressed; however, the development of mechatronic systems should overcome most problems that occur with the currently available mechanical thinners. Shading at critical times is an avenue that could be explored further to ascertain the critical stage when developing fruit are susceptible to enable the determination of the optimal timing and duration of shading. Targeted pruning and bud thinning during the dormant winter period to reduce the floral bud numbers is a valuable option for the precise placement of fruit in optimal positions and to set up the required number of clusters. This review highlighted several tools/techniques that, with further work, can be incorporated into a systematic approach to crop load management in nashi while reducing the risk and cost.

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Some observations on the influence of temperature on the germination of pollen on excised nashi (Pyrus serotinaRehder var.cultaRehder) flowers

Cited by 8 publications

References 10 publications

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

Morphology and Factors Affecting Germination of Litchi Pollen

Crop Load Management in Nashi Pear—A Review

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