Relationships between seed set and fruit weight and shape of nashi (<i>Pyrus serotina</i>Rehder var<i>culta</i>Rehder)

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

doi:10.1080/01140671.1990.10428083

Cited by 6 publications

(8 citation statements)

References 2 publications

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“…Yoneyama (1979) reported that 'Shinsui' was one of the easiest and most reliable cultivars in which to obtain high levels of natural fruit set in Japan, and 'Nijisseiki' one of the hardest. Observations of nashi in the Waikato have similarly found 'Shinsui', to have the highest level of seed set (though less than the optimum seed set per fruit) among the four main commercial cultivars (Rohitha & Klinac 1990). The wider temperature tolerance of 'Shinsui' and its lower temperature optima discussed above may have contributed to this.…”

Section: Resultsmentioning

confidence: 93%

“…This includes the distance from the polliniser and pollen availability (Callan & Lombard 1978), nitrogen status in the plant (Williams 1965), low temperature (Mellenthin et al 1972;Lombard et al 1973), the presence of water on the stigmas (Zuberi & H93065 Received 13 September 1993;accepted 9 June 1994 Dickinson 1985), and the effective flowering period between compatible cultivard (Lombard 1982) are known to affect the fruit set and yield of pome fruit. Rohitha & Klinac ( 1990) and White (1990) showed significant correlations between the number of seeds set per fruit and the fruit size with commercial nashi cultivars in New Zealand. With respect to above mentioned variables, the potential weight gain in fruit through increased fruit set with a right fruit thinning regime is considerable.…”

Section: Introductionmentioning

confidence: 99%

“…However, the observed percentage seed set in open-pollinated nashi in the Waikato, New Zealand can be < 50%, resulting in a significant loss of potential fruit size (Rohitha & Klinac 1990). The factors that govern the completeness of the seed set in the fruit of nashi in the Waikato are still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

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

Rohitha

Klinac

1994

New Zealand Journal of Crop and Horticultural Science

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Pollen germination on excised nashi (Pyrus serotina Rehder var. culta Rehder) styles was compared at six constant temperatures (4, 17, 12, 16, 20, and 25°C). After 24 h pollen germination was highest at 12°C for the cultivar 'Shinsui'. For the cultivars 'Hosui', 'Kosui', 'Nijisseiki', and 'Shinseiki', the optimum temperature for pollen germination was between 16 and 20°C. The (greenskinned) cultivars 'Nijisseiki' and 'Shinseiki' showed higher levels of pollen germination and a higher optimum temperature than the (russeted) cultivars-'Hosui', 'Kosui', and 'Shinsui'. Field temperatures over the flowering period were lower than these in vitro optima, and so may have contributed to the varying levels of seed set observed.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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

Rohitha

Klinac

1994

New Zealand Journal of Crop and Horticultural Science

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“…S-genotypes have been determined for a number of nashi cultivars; the only selfcompatible cultivar described so far has been 'Osa-Nijisseiki', a mutant derived from 'Nijisseiki' [36]. According to Rohitha and Klinac [37], 'Nijisseiki' and, to a lesser extent, 'Kosui' are partially self-compatible. Beutel [38] indicated that 'Nijisseiki' and 'Shinseiki' will set good crops when planted alone or in large single-cultivar blocks.…”

Section: Pollen Compatibilitymentioning

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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“…Fruit growth and size/ shape are also positively associated with seed development and number, respectively, in Malus domestica (apple) (Dražeta et al 2004) and Pyrus spp. (pear) (Callan and Lombard 1978;Rohitha and Klinac 1990).…”

Section: Unpollinated Flowers Of K Pomiferamentioning

confidence: 99%

Breeding behaviour of Kunzea pomifera (Myrtaceae): self-incompatibility, intraspecific and interspecific cross-compatibility

et al. 2010

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To examine breeding system characteristics of the endemic Australian prostrate shrub Kunzea pomifera, artificial hybridisations were undertaken using thirteen different genotypes of K. pomifera, to elucidate: (1) self-incompatibility, (2) intraspecific cross-compatibility in the species and (3) interspecific cross-compatibility with each of K. ambigua and K. ericoides. K. pomifera exhibited very low self-compatibility, with the barrier to self-fertilisation being prevention of pollen-tube growth in the style or ovary. Following intraspecific pollination amongst a number of different genotypes of K. pomifera, 38.4% of pollinated flowers developed fruit; arrest of compatible pollen-tubes in the style, preventing fertilisation, contributes to the low fruit set in this species. Interspecific compatibility was examined between K. pomifera (pistillate parent) and K. ambigua (staminate parent) where seed set per pollinated flower (4.47) was not significantly different from intraspecific crosses (4.66). In crosses between K. pomifera (pistillate parent) and K. ericoides as staminate plant, 0.037% of pollinated flowers produced fruit, with 0.0075 seeds per pollinated flower. Reproductive barriers between these two species were evident in the style of K. pomifera, where the growing tips of the K. ericoides pollen-tubes swelled and ceased to grow.

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Relationships between seed set and fruit weight and shape of nashi (Pyrus serotinaRehder varcultaRehder)

Cited by 6 publications

References 2 publications

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

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

Crop Load Management in Nashi Pear—A Review

Breeding behaviour of Kunzea pomifera (Myrtaceae): self-incompatibility, intraspecific and interspecific cross-compatibility

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