STUDIES on COMPATIBILITY, FRUIT SET and FRUIT QUALITY by DIFFERENT POLLINATORS in ANNA APPLE CULTIVAR [39] Mai I

Arab Univ. J. Agric. Sci., Ain Shams Univ., Cairo, Egypt 82(2), 537-545, 2082 Website: http://ajs.journals.ekb.eg 537 STUDIES ON COMPATIBILITY, FRUIT SET AND FRUIT QUALITY BY DIFFERENT POLLINATORS IN ANNA APPLE CULTIVAR [39] Mai I. Anwar1, Abdel-Ghany2 N.A., Maklad2* M.F. and Nahla A. Awad1 1- Breeding Research Dept., of Fruit Trees, Ornamental and Woody Plants, Horticulture Research Institute, Agricultural Research Center, Giza, Egypt 2- Horticulture Dept., Fac. of Agric., Ain Shams Univ., P.O. Box 68, Hadayek Shoubra 11241, Cairo, Egypt *Corresponding author: [email protected] Received 18 June, 2020 Accepted 24 August, 2020 ABSTRACT crosses. The highest acidity was found in hybrid Anna × Dorsett Golden in except in the first season The apple (Malus domestica) is a member of the TSS values of these crosses were not high and Rosaceae family. It is older than the rose in cultiva- ranged between 11.83 % and 12.83 %. tion and is often referred to as the prince of the rose family. Pollen grains of Dorsett Golden, E25 and Ein Keywords: Apple cultivars, Anna, Cross-compati- Shemer were used to investigate their compatibility bility, Pollen viability, Fruit set, Fruit quality and incompatibility with Anna cultivar under the Egyptian climatic conditions during two successive INTRODUCTION experimental seasons of 2016 and 2017. The fluorescence microscope was used to determine the Pollination is an important step in apple quality degree of pollen tube growth in style tissue after manufacturing. Although many environmental fac- specific pollination treatments. Degree of self and tors can result in poor pollination and lower fruit set- cross compatibility and or incompatibility were de- ting, the genetic makeup and quality of an orchard's termined, initial, and final fruit set percentage were apple varieties are key determinants of pollination calculated. Pollination treatments revealed that, pol- success. The cultivated apple (Malus x domestica) lens of the four apple cultivars exhibited high rate of and several other economically significant members the viability after 24 hr. in T.T.C test. Growth of pol- of the Rosaceae or rose family (pears, peaches, len tube of the tested cultivars exhibited different prunes, sweet and tart cherry) contain a complex bi- pattern of compatibility, the pollen tubes of Dorsett ochemical mechanism that prevents the ovules from Golden and Ein Shemer cultivars showed different being fertilized by the variety's own (also known as levels of cross-compatibility when fertilized in Anna cultivar) pollen, the initial phase in fruit growth (Hua style tissue. The pollen tube of E25 cultivar grew et al 2008). This method, known as self-incompati- slowly with heavy deposition of calluses along to the bility (SI), places a lot of restrictions on both the ap- tube where its growth stopped in the lower part of ple grower and breeder, but it does have the benefit Anna style four days after pollination. Therefore, of keeping apple versatile. For a so-called "out- they need pollinizer cultivars as for good fruit set. crosser," this means that apple offspring differ from On the other hand, Anna self-pollination seemed to their parents, allowing them more capacity to re- be self-incompatible and recorded lowest initial of spond to illness and stress. In the past few decades, fruit set percentage in the first and second seasons. self- and cross-incompatibility has grown, and new The combinations of Anna × Dorsett Golden exhib- methods (molecular markers) are available to help ited maximum percentage of initial and final fruit set the SI 's challenges (Orcheski and Brown, 2012). in the two seasons followed by Ein Shemer pollens Structures of self-incompatibility (SI) can be classi- in both seasons. Insignificant differences were fied into two main groups: Gametophytic Self-In- noted in fruit weight and fruit volume among all compatibility (GSI) and SSI. (Maryam Bagheri and 538 Mai Anwar; Abdel-Ghany; Maklad and Nahla Awad Ahmad Ershadi, 2019). GSI is the most frequent (2) Pollination experiments type of SI in the Solanaceae, Rosaceae and Papa- veraceae families (De Nettancourt 2001). Com- On Anna trees (as a female parent) self-pollina- mercial fruit in pear orchards is cross-pollinated and tion and cross-pollination were carried out, ten Anna requires at least two compatible cultivars that flower female parents were identical in vigor and size and simultaneously to produce fruit (Zisovich et al the same bearing process as much as possible in 2010). Apple has a gametophytic incompatibility randomized full block design, 6 panicles (panicle as multi-allelic system controlled by a single S gene a one replicate) from each tree were chosen to con- (Frankel et al 1977). Several apple cultivars are duct the combination by each tested pollinate male considered to be mutually incompatible (Ishiyama parent. Flowers were selected at a similar stage of et al 1995; Way, 1995 and Sakurai et al 2000). In- development, each panicle was well bagged with a compatibility and compatibility between parents (fe- pergamin bag before anthesis to prevent insect pol- male and male parents) are important factors in the lination and the pollen grains of each pollinator were crop production (Abou El Nasr et al 1997). collected for hand pollination after emasculation In this respect, Anna apple cultivar (as a female (cross-pollination), then each panicle was bagged parent) was investigated for their self, cross-com- after being pollinated in pergamin bags. Four an- patibility and or incompatibility level between other of Anna panicles were chosen for each polli- Dorsett Golden, E25 and Ein Shemer which uses as nate male parent from each tree and left until fruit pollinizers for Anna cultivar to improve fruit set and setting. At anthesis and at the balloon stage, the fruiting. number of total flowers was numbered. After 3 weeks of pollination (initial fruit set) or anthesis time MATERIALS AND METHODS and 2 weeks before harvest (final fruit set) number of stetted fruits was counted. The percentage of the Plant materials initial and final fruit collection for different pollination treatments was determined as follows: This study was conducted during two consecu- Percentage of initial fruit set = (Number of fruitlets / tive seasons of 2016 and 2017 at the private or- total number of flowers) x 100. chard, El-Sadat city, Monefeia governorate. Three Percentage of final fruit set = (Number of stetted cultivars of Apple namely, Dorsett Golden, E25 and fruits / total number of flowers) x 100. In open polli- Ein Shemer were used to evaluate pollen tube nation treatment, enough panicles were labeled growth as potential factors limiting apple fruit set pa- without any treatment and the flowers were left un- rameters and, to define the effective pollinizer for der the natural conditions of the orchard. Anna apple cultivar (as a female parent). Therefore, the following crosses had been done: (3) Microscopic preparations a. Anna selfing pollination. b. Cross pollination by Dorsett Golden pollens. From each combination, fifteen pistils/panicle c. Cross pollination by E25 pollens d. Cross polli- collected just After pollination and set in FPA for nation by Ein Shemer pollens. seven consecutive days after pollination (Formalin: e. Anna open pollination as a control. propionic acid: alcohol, 90:5:5). Pistil samples were softened in 8N NaOH for 2 hours, washed in distilled Methods water for 24 hours and dyed in 0.1% aniline blue (W / S), dissolved in 0.1 N K3PO4 and analyzed with (1) Pollen viability Leica fluorescence microscope (WILD LEITZ GMBH, 020-505-030, LEITZ WETZLAR GER- Anthers of the four cultivars studied were col- MANY) according to the method of Kho and Baer lected at the balloon stage from the flowers and held (1970) and Maklad (2015). at room temperature on paper sheets throughout Pomological characteristics of fruit from hybridi- the night, to promote dehiscence. Pollen viability zation: including physical fruit properties i.e. the was calculated using a staining solution of 2, 3, 5 weight of the fruit (gm), volume (cm3), fruit length, triphenyl tetrazolium chloride (T.T.C) (1 part 10% fruit diameter in cm, number of seeds/fruit, fruit pulp T.T.C.: 10 part 60% sucrose) according to Oberle thickness and some chemical properties including and Watson (1952). T.S.S% and acidity according to A.O.A.C (1990) as g malic acid / 100 ml flesh. AUJASCI, Arab Univ. J. Agric. Sci., 22(2), 2082 Studies on compatibility, fruit set and fruit quality by different pollinators 539 in anna apple cultivar Statistical analysis Table 1. Pollen grains viability in T.T.C of Dorsett Golden, E25, Ein Shemer and Anna apple cultivars For each pollination procedure, the experi- in 2016 and 2017 seasons mental design was a complete randomized block with 10 trees and 6 panicles per branch (panicle as Percentage of the valiability of pollen grains in one replicate). The data collected during the two T.T.C after 24h. seasons have been statistically analyzed using the Season 2016 Season 2017 variance analysis (Snedecor and Cochran, 1972) Dorsett Golden 94.28 A 95.49 A means differentiated by 5 percent using the multi- E25 90.60 BC 90.92 B range test of Duncan (Duncan, 1955). Ein Shemer 91.79 B 91.69 B Anna 89.33 C 89.85 B RESULTS AND DISCUSSION Values having the same letter within the same column are not statically different at 5% level Pollen viability Compatible pollinator efficiency Table (1) illustrate the pollen viability of Dorsett Golden, E25, Ein Shemer and Anna apple cultivars Cross compatibility and/or incompatibility in the two seasons of this research. Pollens of the Dorsett Golden apple cultivar exhibited highest sig- Microscopic examination showed growth of pol- nificant rate of the viability after 24 hr.

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