Kerontokan buah sering terjadi dan menyebabkan rendahnya panen buah. Informasi penggunaan hormon GA3 dalam menekan kerontokan buah pada jeruk pamelo masih belum tersedia. Riset ini bertujuan untuk mengkaji peranan GA3 terhadap kerontokan dan kualitas buah jeruk pamelo berbiji dan tidak berbiji. Penelitian ini dilaksanakan pada Desember 2019 sampai Juni 2020 di Desa Tambakmas, Kecamatan Sukomoro Kabupaten Magetan. Desain percobaan menggunakan rancangan tersarang, dimana faktor utama adalah kultivar Bali Merah 1 dan Bali Merah 2 dan faktor tersarang adalah penyemprotan GA3 tanpa disemprot GA3, penyemprotan GA3 pada 1 minggu setelah antesis MSA dan penyemprotan GA3 pada 1 dan 3 MSA. Bali Merah 1 tergolong pada pamelo berbiji, sedangkan Bali Merah 2 adalah pamelo tidak berbiji. Peubah pengamatan meliputi konsentrasi GA3 buah pada 4, 5, dan 6 MSA, final set, jumlah buah rontok, bobot dan diameter buah, bagian dapat dimakan BDD, padatan terlarut total PTT, asam tertitrasi total ATT, rasio PTT/ATT dan vitamin C. Hasil menunjukkan bahwa penyemprotan GA3 meningkatkan final set namun tidak memberikan pengaruh nyata pada bobot buah, diameter buah, ATT, rasio PTT/ATT dan kandungan vitamin C. Penyemprotan GA3 pada 1 dan 3 MSA menekan jumlah buah rontok serta meningkatkan konsentrasi GA3 buah pada 4, 5, dan 6 MSA, BDD dan PTT buah. Kata kunci asam tertitrasi total, final set, padatan terlarut total, Vitamin C Discover the world's research25+ million members160+ million publication billion citationsJoin for free 295Kalsum et al. / J. Agron. Indonesia 493295-301Desember 2021* Penulis untuk korespondensi. e-mail slmtsanto Wafat pada Maret 2020ISSN 2085-2916 e-ISSN 2337-3652Tersedia daring Agron. Indonesia, Desember 2021, 493295-301DOI GA3 terhadap Kerontokan dan Kualitas Buah Jeruk Pamelo Berbiji dan Tidak Berbiji The Role of GA3 on Fruit Drop and Fruit Quality of Seeded and Seedless Pummelo Ummu Kalsum1,2, Slamet Susanto3*, Ahmad Junaedi3, Nurul Khumaida3+, dan Heni Purnamawati3 1Program Studi Agronomi dan Hortikultura, Sekolah Pascasarjana, Institut Pertanian Bogor 2Program Studi Agroteknologi, Fakultas Teknologi Industri, Universitas GunadarmaJl. Margonda Raya No. 100, Depok 16424, Indonesia3Departemen Agronomi dan Hortikultura, Fakultas Pertanian, Institut Pertanian Bogor IPB University, Jl. Meranti, Kampus IPB Darmaga, Bogor 16680, IndonesiaDiterima 8 November 2021/Disetujui 15 Desember 2021ABSTRACTFruit drop occurs frequently and causes low fruit harvesting. The information about the use of the hormone GA3 in suppressing fruit drop in pummelo is still not available. This research aimed to examine the role of GA3 on fruit drop and fruit quality in seeded and seedless pummelo. This research was conducted from December 2019 until June 2020 in Tambakmas Village, Sukomoro District, Magetan Regency. The experiment used a nested design with two factors, cultivars as the main factor Bali Merah 1 and Bali Merah 2 and spraying GA3 as a nested factor without spraying GA3, sprayed with GA3 at 1st week after anthesis WAA, and sprayed with GA3 at 1st and 3rd WAA. Bali Merah 1 belongs to seeded pummelo, while Bali Merah 2 is a seedless pummelo. The observation variables consisted of the concentration of GA3 at 4th, 5th, and 6th WAA, final set, the number of fruit drop, fruit weight and diameter, edible portion, total soluble solids TSS, total titratable acidity TTA, TSS/ATT ratio, and vitamin C. The result showed that the GA3 spraying increased the final set of pummelo but the treatment had no significant affected on fruit weight, fruit diameter, TTA, TSS/TTA ratio, and vitamin C content. The GA3 spraying at 1st and 3rd WAA suppressed fruit drop and increased the GA3 concentration of fruit at 4th, 5th and 6th WAA, the edible portion and TSS of pummelo final set, total titratable acidity, total soluble solids, vitamin CABSTRAK Kerontokan buah sering terjadi dan menyebabkan rendahnya panen buah. Informasi penggunaan hormon GA3 dalam menekan kerontokan buah pada jeruk pamelo masih belum tersedia. Riset ini bertujuan untuk mengkaji peranan GA3 terhadap kerontokan dan kualitas buah jeruk pamelo berbiji dan tidak berbiji. Penelitian ini dilaksanakan pada Desember 2019 sampai Juni 2020 di Desa Tambakmas, Kecamatan Sukomoro Kabupaten Magetan. Desain percobaan menggunakan rancangan tersarang, dimana faktor utama adalah kultivar Bali Merah 1 dan Bali Merah 2 dan faktor tersarang adalah penyemprotan GA3 tanpa disemprot GA3, penyemprotan GA3 pada 1 minggu setelah antesis MSA dan penyemprotan GA3 pada 1 dan 3 MSA. Bali Merah 1 tergolong pada pamelo berbiji, sedangkan Bali Merah 2 adalah pamelo tidak berbiji. Peubah pengamatan meliputi konsentrasi GA3 buah pada 4, 5, dan 6 MSA, final set, jumlah buah rontok, bobot dan diameter buah, bagian dapat dimakan BDD, padatan terlarut total PTT, asam tertitrasi total ATT, rasio PTT/ATT dan vitamin C. Hasil menunjukkan bahwa penyemprotan GA3 meningkatkan final set namun tidak memberikan pengaruh nyata pada bobot buah, diameter buah, ATT, rasio PTT/ATT dan kandungan vitamin C. Penyemprotan GA3 pada 1 dan 3 MSA menekan jumlah buah rontok serta meningkatkan konsentrasi GA3 buah pada 4, 5, dan 6 MSA, BDD dan PTT buah. Kata kunci asam tertitrasi total, final set, padatan terlarut total, Vitamin C 296Kalsum et al. / J. Agron. Indonesia 493295-301Desember 2021PENDAHULUAN Permasalahan dalam produksi tanaman jeruk seringkali terjadi, seperti kerontokan buah pada stadia awal perkembangan buah dan kerontokan menjelang panen. Kedua hal tersebut akan mengurangi produksi buah. Taiz dan Zeiger 2002 menyatakan bahwa absisi atau kerontokan buah merupakan proses lepasnya suatu buah dari pohon. Absisi ini terjadi pada zona absisi yang terletak pada tangkai buah, dimana proses ini umumnya diawali dengan diferensiasi suatu lapisan absisi pada zona absisi. Bisht et al. 2018 yang menyatakan bahwa absisi organ buah dapat terjadi pada awal perkembangan buah atau saat buah akan memasuki periode kultivar jeruk pamelo berbunga hanya satu kali dalam setahun, yakni mayoritas berbunga pada akhir Oktober sampai Desember Kalsum et al., 2021. Pembungaan yang terjadi hanya sekali ini memerlukan perhatian untuk meningkatkan jumlah buah panen dan keberlanjutan ketersediaan buahnya. Peningkatan jumlah buah panen tergantung pada kemampuan setiap kultivar dalam mempertahankan retensi buah pada pohon sampai matang. Li et al. 2017 dan Khefifi et al. 2020 melaporkan bahwa kerontokan buah pada waktu tertentu dipengaruhi oleh hara buah, potensi genetis, konsentrasi hormon dan lingkungan. Susanto et al. 2011 menyatakan bahwa jeruk pamelo di Indonesia terbagi menjadi pamelo berbiji biji per buah >10 dan pamelo tidak berbiji biji per buah 400 g serta dikategorikan dalam ukuran kode 5 1101-1300 g. Penyemprotan GA3 tidak memberikan pengaruh nyata pada bobot dan diameter membujur buah. Bons et al. 2015 menyatakan bahwa aplikasi GA3 setelah bunga mekar tidak selalu meningkatkan bobot buah panen, namun terjadi peningkatan ukuran di awal stadia disebabkan peningkatan sementara pembelahan sel di dinding ovarium. Diameter buah melintang dan membujur dari semua perlakuan sudah melebihi standar minimum Codex UNECE 2017 yaitu 10 cm. Dengan demikian, buah pamelo dari semua perlakuan sudah memiliki nilai komersial yang baik dari segi ukuran, baik bobot maupun diameter buah pamelo tidak berbiji lebih tinggi dibandingkan pamelo berbiji Pamelo tidak berbiji Bali Merah 2 menghasilkan BDD yang lebih tinggi dari pamelo berbiji diduga karena pengaruh jumlah biji yang terdapat di dalam buah. Bobot buah pamelo berbiji dan tidak berbiji yang sama namun memiliki jumlah biji yang berbeda mempengaruhi BDD, dimana menurut Kalsum et al. 2021 jumlah biji per buah Bali Merah 1 >40 biji sedangkan Bali Merah 2 bijinya Bali Merah 1>Bali Merah 2. Seeded pummelo was not significant difference with seedless pummelo on several variables, except the total titrable acidity TTA content seeded group > seedless group. Adas Duku became the best cultivar compared to the other three cultivars in several characteristics, such as the lowest peel thickness, the highest in the edible portion, the total soluble solids TSS and TTA of flesh fruit. Nidhi ChauhanJyoti Bharti SharmaWasif MirKanchan RanaGibberellins are the organic compounds which tend to regulate several metabolic processes in the plants. They play an important role in the enhancement of efficiency of fruit crops in terms of growth, quality and yield. GAs are naturally synthesized by the higher plants but in insufficient amounts. Therefore, the exogenous applications of GA at different concentrations and at different stages of growth drastically increase the seed germination, stem elongation, shoot initiation, flower induction, flower inhibition, fruit set, fruit development and modify several other vital processes in the fruit crops. Similarly, Promalin is a mixture of two naturally occurring plant growth regulators gibberellic acid 4 and 7 GA₄+₇, which causes cell enlargement and elongation, and 6-benzyladenine 6-BA which promotes cell division. Promalin has been reported very effective especially in temperate fruit crops like apple, pear, cherry etc. where it has proven beneficial for increased fruit N, Susanto S, Aziz SA, Suketi K, Dadang. 2020. The diversity of kristal’ guava Psidium guajava fruit quality in response to different altitudes and cultural practices. Biodiversitas 21 3310-3316. The current study aimed to compare the quality of kristal’ guava fruit harvested from different altitudes under different cultural practices. The study was conducted from January to March 2019. Four treatments were examined, fruit from low altitude-intensive cultural LI, low altitude-less intensive cultural LI, middle altitude-intensive cultural MI, and middle altitude-less intensive cultural ML. All treatments were arranged in a completed randomized design and each treatment had five trees as replicates The findings of the study showed that there was a variation of fruit quality in response to different altitudes and cultural practices. The fruits harvested from low altitudes were significantly bigger and heavier than the fruits harvested from middle altitude, irrespective of cultural practices. With regard to fruit softness, the fruits from middle altitudes were crispier than fruits from the low altitude. The chemical qualities of the fruits, indicated by TSS/TA ratio and vitamin C, were better in guava orchard under intensive cultural practice than less intensive cultural practice. The intensive cultural practice also improved the guava fruit size as compared to the less intensive cultural practice. This finding may be attributed to pruning which is performed in intensive cultural practice. More beneficial metabolites for human health such as vitamin E and caryophyllene were found in fruit from low temperature, viral diseases and salinity are the major limiting factors in sustaining and increasing tomato productivity. To tackle the different biotic and abiotic stresses in tomato cultivation application growth regulators have been considered as right choice for scientists and farmers. Plant growth regulators also called plant hormones are numerous chemical substances that profoundly influence the growth and differentiation of plant cells, tissues and organs. Plant growth regulators function as chemical messengers for intercellular communication. In tomato, different growth regulators play a pivotal role in germination, root development, branching, flower initiation, fruiting, lycopene development, synchronization and early maturation, parthenocarpic fruit development, ripening, TSS, acidity, seed production etcetera. To boost the tomato production in India these versatile resources greatly help the professionals and researchers. Keeping the importance of growth regulator in tomato production in mind this review paper is fruit abscission usually occurs at the final stage of fruit maturation but in some areas of citrus production, in advance of the usual harvest period, and sometimes suddenly and intensely. The reasons for this precocious citrus fruit abscission remains unclear. Therefore, the aim of this study was to try to clarify what the determinants of this phenomenon are. A multi-site experimentation was carried out on six orange cultivars, in Corsica, Spain and Tunisia where the phenomenon of early massive fruit drop varies. Climatic parameters, fruit maturity parameters and fruit detachment force FDF were recorded along the fruit maturation period. Respectively to the fruit drop, the FDF decreased in Tunisia and in Spain until the fruit falls, whereas in Corsica, it remained relatively constant throughout fruit maturation. Although data on fruit maturity parameters rind color, acidity and total soluble solids differed at the three sites, their evolution was similar during the period of maturation. FDF was not related to changes in any fruit maturity parameters, and more likely depended on changes in temperatures on days when the mean temperature was above 13 • C. Massive fruit abscission could be linked to the earlier more rapid restart of vegetative growth in Tunisia and Spain than in fruits are mainly consumed as fresh fruit and processed juice products. They serve as nutritional and a tasty diet in our daily life. However, the formidable bitterness and delayed bitterness significantly impact the citrus industry attributable to the two major bitter compounds naringin and limonin. The extremely sour and acidic also negatively affects the sensory quality of citrus products. Citrus breeding programs have developed different strategies to improve citrus quality and a wealth of studies have aimed to uncover the genetic and biochemical basis of citrus flavor. In this minireview, we outline the major genes characterized to be involved in pathways shaping the sweet, bitter, or sour taste in citrus, and discuss briefly about the possible approaches to modify citrus taste by genetic study aimed to evaluate the effect of GA3 gibberellic acid application on growing pineapple 'Pérola' fruits, and also the harvest season on yield, and fruit quality. The experimental design used was randomized blocks in 5×2 factorial design, being the first factor the application of GA3, and the second the harvest season, totaling in 10 treatments with four replicates, in split-plot plots. The treatments tested were 1 GA3 application after the appearance of the first flower open on the inflorescence; 2 application of GA3 after the closing of the flowers in the inflorescence; 3 application of GA3 45 days before the first harvest; 4 two applications of GA3 one after the closing of flowers and another 45 days before the first fruits harvest; and 5 without application of GA3. Two harvest seasons were evaluated 150 and 180 days after the floral induction. The phytoregulator Pro-Gibb in a concentration of 200 mg L-1 of GA3 was adopted. The variables assessments were fruit length with crown and without, crown length and mass, crownless fruit mass, average fruit mass and yield, titratable acidity, total soluble solids, and pH of the juice. The harvest of pineapple fruits held 180 days after floral induction, combined with an application of GA3 45 days before the harvest, provided greater yield while maintaining and improving the quality of pineapple 'Pérola' fruits. The use of GA3 did not influence the pineapple yield when the harvest is performed early, 150 days after flower induction. RESUMO Este trabalho objetiva avaliar o efeito da aplicação de GA 3 ácido giberélico no fruto de abacaxi 'Pérola' em desenvolvimento e a época de colheita na produtividade e qualidade do fruto. O delineamento experimental foi o de blocos casualizados em esquema fatorial 5x2, sendo o primeiro fator época de aplicação do GA 3 e o segundo a época de colheita, totalizando 10 tratamentos com quatro repetições, com parcela subdividida. Os tratamentos testados foram 1 aplicação do GA 3 após o aparecimento da primeira flor aberta na inflorescência; 2 aplicação do GA 3 após o fechamento das flores na inflorescência; 3 aplicação do GA 3 aos 45 dias antes de realizar a primeira colheita; 4 duas aplicações do GA 3 uma após o fechamento das flores e outra aos 45 dias antes da primeira colheita dos frutos; e 5 sem aplicação de GA 3. E duas épocas de colheita 150 e 180 dias após a indução floral. Utilizou o fitorregulador Pro-Gibb como concentração de 200 mg L-1 de GA 3. As variáveis avaliadas foram comprimento do fruto com e sem coroa, comprimento e massa da coroa, massa do fruto sem coroa, massa média do fruto e produtividade, acidez titulável, teor de sólidos solúveis totais e pH do suco. A colheita dos frutos de abacaxi realizada, aos 180 dias após a indução floral, com aplicação do GA 3 aos 45 dias antes da colheita, proporcionou maior produtividade mantendo e melhorando a qualidade dos frutos de abacaxi 'Pérola'. O uso do GA 3 não influência na produtividade do abacaxi quando a colheita é realizada precoce, ou seja, aos 150 dias após a indução In Citrus spp., gibberellic acid GA has been proposed to improve different processes related to crop cycle and yield. Accordingly, many studies have been published about how GA affects flowering and fruiting. Nevertheless, some such evidence is contradictory and the use of GA applications by farmers are still confusing and lack the expected results. Purpose This review aims to collate, present, analyze and synthesize the most relevant empirical evidence to answer the following questions i how does gibberellic acid act on flowering and fruiting of citrus trees?; ii why is all this knowledge sometimes not correctly used by farmers to solve yield problems relating to flowering and fruit set? Methods An extensive literature search to obtain a large number of records about the topic was done. Searches were done in five databases WoS, Scopus, Google Academics, PubMed and Scielo. The search string used was "Gibberellic acid" AND "Citrus". Records were classified into 11 groups according to the development process they referred to and initial data extraction was done. Records related with flowering and fruit set were drawn, and full texts were screened. Fifty-eight full text records were selected for the final data extraction. Results Selected studies were published from 1959 to 2017 and were published mainly in Spain, USA, Brazil and Japan. Twelve species were studied, and Citrus sinensis, C. reticulata and C. unshiu were the principal ones. Most publications with pre-flowering treatments agreed that GA decreases flowering, while only 3 out of 18 did not observe any effect. In most of these studies, the effect on fruit set and yield was not evaluated. Studies with treatments at full bloom or some weeks later mostly reported increased fruit set. However, these increases did not imply higher yields. The results on yield were highly erratic as we found increases, decreases, no effects or variable effects. Conclusions Despite some limitations, the action of GA related to cell division and growth, stimulating the sink ability of the organ and discouraging its abscission, has been clearly established through reviewed studies. GA applications before flowering counteract the floral induction caused by stress reducing flowering. However, on adult trees under field conditions, reducing flowering by applying GA would be difficult because it would be necessary to previously estimate the natural floral induction of trees. During flowering and fruit set, many problems may arise that limit production. Only when the problem is lack of fruit set stimulus can GA applications improve yields. However, much evidence suggests that the main factor-limiting yield would be carbohydrate availability rather than GA levels. GA applications increased fruit set often transiently, but this increase did not mean improved Fenech Iraida AmayaVictoriano ValpuestaMiguel A BotellaThroughout evolution, a number of animals including humans have lost the ability to synthesize ascorbic acid ascorbate, vitamin C, an essential molecule in the physiology of animals and plants. In addition to its main role as an antioxidant and cofactor in redox reactions, recent reports have shown an important role of ascorbate in the activation of epigenetic mechanisms controlling cell differentiation, dysregulation of which can lead to the development of certain types of cancer. Although fruits and vegetables constitute the main source of ascorbate in the human diet, rising its content has not been a major breeding goal, despite the large inter- and intraspecific variation in ascorbate content in fruit crops. Nowadays, there is an increasing interest to boost ascorbate content, not only to improve fruit quality but also to generate crops with elevated stress tolerance. Several attempts to increase ascorbate in fruits have achieved fairly good results but, in some cases, detrimental effects in fruit development also occur, likely due to the interaction between the biosynthesis of ascorbate and components of the cell wall. Plants synthesize ascorbate de novo mainly through the Smirnoff-Wheeler pathway, the dominant pathway in photosynthetic tissues. Two intermediates of the Smirnoff-Wheeler pathway, GDP-D-mannose and GDP-L-galactose, are also precursors of the non-cellulosic components of the plant cell wall. Therefore, a better understanding of ascorbate biosynthesis and regulation is essential for generation of improved fruits without developmental side effects. This is likely to involve a yet unknown tight regulation enabling plant growth and development, without impairing the cell redox state modulated by ascorbate pool. In certain fruits and developmental conditions, an alternative pathway from D-galacturonate might be also relevant. We here review the regulation of ascorbate synthesis, its close connection with the cell wall, as well as different strategies to increase its content in plants, with a special focus on fruits.