International Journal of Horticultural Science and Technology
Volume:8 Issue: 2, Spring 2021

Beneficial microorganisms which help plants to grow better especially under stress conditions are known as plant growth-promoting bacteria (PGPB). These biotic agents, especially Bacillus subtilis have well-known role in plant growth promotion and induction of tolerance to stress in plants. They are deemed to act as bio-active and eco-friendly agents to facilitate plant growth under stressful conditions and even to control postharvest decays. Microbial antagonists, including B. subtilis, effectively control postharvest diseases of different fruits, vegetables and flowers, which is manifested in prolonged storage period and shelf/vase life, while preserving qualities and reducing weight losses. In this review paper we highlight the potential benefit of PGPBs especially B. subtilis, as important biotic useful agents to help horticultural plant perform better under stressful conditions and to delay senescence and control the postharvest deterioration through activation of different defense mechanisms. We further elaborate the underlying mechanisms that PGPB used to help plants to cope with stressful conditions. Nevertheless, the mechanisms of PGPB especially B. subtilis action requires further detailed investigations to fully utilize their potentials in horticulture industry.

Planting date is an important factor which directly related to crop production in a specific area. Different planting time may affect crop yield and quality due to varying climatic conditions at different stages of crop growth and development. The present experiment was laid out to investigate the effect of planting date at an interval of 15 days during winter season of 2019-20 on the yield and quality of cherry tomato. The potentiality of fruiting in the winter season was evaluated by planting on November 15, November 30, December 15, December 30 and January 14. Data on yield and quality attributes of cherry tomato like plant height, number of fruits per plant, fruit yield per plant (g), yield (t ha-1), TSS (%), pH and vitamin C contents (mg 100 g-1) were recorded. Results revealed that planting time had significant effects on the yield and quality parameters of cherry tomato. Cherry tomato performed better on 30 November planting date in respect of yield and vitamin C content due to favorable climatic conditions at different growing stages as per requirements that may lead to higher yield and quality of fruits.

A field-based experiment was carried out in Rukum (East), Nepal, from February to June 2020, to assess the effect of different methods and dates of grafting on the graft take rate of Persian walnut (Juglans regia L.) in field condition. The experiment comprised ten treatments with combination of two factors. The two factors included the grafting dates including: 13th, 19th, and 26th of February, 4th and 11th of March and grafting methods including: outdoor grafting and bench grafting (tongue grafting in both). The experiment was laid out in a Randomized Complete Block Design with three replications. The findings revealed that bench grafting resulted in significantly better outputs than outdoor method for length of scion (at 30 and 60 days after grafting) and graft take rates. Bench grafting showed 44% graft take followed by outdoor grafting (38% graft take). Plants grafted on 13th and 19th of February showed statistically better results for growth performance over the other dates. Plants grafted on 19th of February showed 67% graft take with 53% saleable plants, but statistically similar to the plants grafted on 13th and 26th of February. The earliest bud burst was observed in plants grafted on 13th and 19th of February in 31 and 33 days, respectively. Bench grafting on 19th February showed significantly higher length of scion (16.4 cm) at 60 days after grafting. However, non-significant results were seen for other parameters due to the interaction. Therefore, bench grafting on 13th,19th and 26th of February led to the best graft take in Persian Walnut.Abbreviations: CV: Coefficient of Variation, LSD: Least Significant Difference, ha: hectare, mt: Metric tons, PMAMP: Prime Minister Agriculture Modernization Project, RCBD: Randomized Complete

Vivipary is not a rare finding in papaya fruit. However, this short communication describes the unusual germination of seedling within intra-ovarian ovary. The seedling is attached at two ends of the immature ovary: by radicle at one end, and by elongated tubular structure at the other end. The tubular structure, probably a hypocotyl, mimics an umbilical cord connecting the growing fetus with that of placenta in human embryonic development.

Fig tree (Ficus carica L.) is characterized by a wide genetic diversity in Tunisia although it is considered as a secondary species. In Kerkennah islands, despite several biotic and abiotic stresses, local population has conserved the fig germplasm. This species is very well suited to the harsh environments. In order to enhance on farm conservation of fig genetic resources and to have inventory of related traditional knowledge (TK), a global survey was conducted among a wide range of stakeholders and local governmental agencies in Kerkennah archipelago. For this purpose, prospections were done during two successive years covering the totality of the islands. A total of 9 locations and 26 sub-locations were visited. Twenty four farmers were solicited. Surveys have taken into account sex, age of farmers, predominant agricultural activities of farmers, field area, fig cultivated varieties, land management, traditional knowledge, production and its use, source of incomes and marketing of production. Participatory Four Cell Analysis (FCA) allowed the classification of fig cultivars regarding the threat level of loss and the adequate manner of conservation. Results of this study showed that it is imperative to pay particular attention to threatened and rare cultivars. Hence, the importance to conserve such diversified germplasm. On farm conservation program is a suitable alternative for such region for preservation of traditional knowledge, cultivars rehabilitation and a sustainable agriculture.

One of the best interventions to hasten seed germination and seedling development is the exogenous application of phytohormone. This study evaluated the germination and seedling development of rubber seeds in response to gibberellic acid (GA3) and organic growth media under nursery condition. The experiment was arranged in a 4x3 factorial experiment in completely randomized design (CRD) with three replications. Growth media (including: top soil, TS; TS + rice hull, RH; TS + chicken dung, CD; TS + vermicast, VC) were considered as Factor A, and different concentrations of GA3 (0, 50, and 100 ppm) were comprised as the Factor B. Newly fallen seeds (with no defects) from existing ‘RRIM 600’ rubber tree plantation were collected and used in the experiment. Seeds were subjected to float in GA3 solutions based on corresponding treatments for 18 h prior to sowing in different organic growth media. GA3 (100 ppm) led to the earliest emergence, highest germination percentage and normal seedlings with least mortality. The TS+VC was the best growth media influencing germination. The TS+VC media regardless of the concentration of GA3 caused 100% normal seedlings. Likewise, the combination of TS+CD as growth media and 100 ppm of GA3 also produced promising percentage of normal seedlings of rubber with 97.33%. Seedling mortality was lessen using the combination of TS+VC as growth media and 100 ppm GA3. Generally, application of 100 ppm GA3 and top soil mixed with vermicast as growth media provoked better seed germination and early seedling development in rubber.

To evaluate the effect of salicylic acid (SA) on seed germination of black bean plant under saline conditions, seeds were primed with salicylic acid (0, 2, 10, and 20 mM) and germinated under salt stress (0, 50, and 100 mM NaCl). The measured parameters included the percentage and rate of seed germination, seedling length and dry weight, malondialdehyde and hydrogen peroxide levels, and activity of catalase, ascorbate peroxidase and guaiacol peroxidase in the seedlings. Results showed the values of germination indices decreased with increasing the level of salt stress. However, SA priming (10 mM) alleviated the harmful effects of salt stress in black bean. SA increased seed germination percentage by 72% and 45% at 50 and 100 mM NaCl respectively, compared to the control condition. Germination rate augmented by 33% (at 50 mM NaCl) and 60% (at 100 mM NaCl) by SA priming compared to the seeds exposed to salt stress alone. Seedlings dry weight (+ 51% at 50 mM and + 34% at 100 mM) and length (+ 57% at 50 mM and + 29% at 100 mM NaCl) were significantly higher by priming with 10 mM salicylic acid, compared to exclusively salt stress-treated seeds. SA priming increased antioxidant enzymes activities and decreased the levels of lipid peroxidation and hydrogen peroxide in salt stressed black bean seedlings. In conclusion, salicylic acid priming (particularly at 10 mM) enhances salt tolerance in black bean via lessening of oxidative stress.

Different sources of nitrogen fertilizers are being used in olive orchards, of which urea is widely used by olive growers. However, nano-chelated nitrogen (nano-N) is a newly found feature of the fertilizer with very little known information. In the current research, the impact of foliar spray of two nitrogen sources; urea (U) and nano-N on oil content and quality of olive cv. ‘Zard’ during two consecutive seasons were investigated. The olive trees were sprayed with 2.21 g (U1) and 2.95 g (U2), and 6 g nano-N1 and 8 g nano-N2 at several phenological stages of olive tree. The detailed observations showed that U1 significantly increased fruit yield. Monounsaturated fatty acid and the ratio of oleic acid to linoleic acid were increased by the nitrogen treatments, especially with nano-N2, whereas it decreased in the case of saturated fatty acid and polyunsaturated fatty acids. The application of both fertilizer sources improved the leaf mineral compositions as well as the oil quality such as free fatty acids, peroxide activity, K232 and K270 extinction coefficients, the chlorophyll and carotenoid pigments. Total phenolic content of the oil in olive trees sprayed with urea was lower than those treated with nano-N. In contrast, the oil antioxidant capacity was high in those trees treated with nano-N. Overall, the results showed that nano-fertilizer, especially nan-N2 treatment rather than urea, is an effective approach to improve oil quality.