Studies on growth and yield of shoot pruning in guava (Psidium Guajava L.) Cvs. Lalit and Shweta

Introduction

Guava (Psidium guajava L.), a Myrtaceae family member, is a prolific and profitable fruit crop that thrives in a variety of soil and agro-climatic conditions. It has been widely embraced and is widely farmed in India. It has become a significant fruit crop in India, it is produced 4304000 MT of guava from a 287000-ha area with an average productivity of 14.99 t/ha. Out of 99.07 million tonnes of total fruit production, it contributes 4.07% in national fruit basket production (DAFW, 2021). Although, it is grown throughout the India's in tropical and subtropical regions, the major guava growing states are Uttar Pradesh, Bihar, Rajasthan, Madhya Pradesh, Maharashtra, and West Bengal. The Allahabad region of Uttar Pradesh is regarded as one of the world's greatest guava growing regions (Mitra and Sanyal, 2004) [6] . Allahabad is known for producing the highest quality fruits in India and the world (Mitra and Bose, 1985) [5] . In Uttar Pradesh, guava is cultivated in area around 49.53 (000 ha) and it produced 928.44 (000 MT) according to the data (Horticultural statistic at a glance 2018). Guava is one of the important fruit crop of the Bundelkhand region of UP and MP. It is also known as "apple of the plain" and "poor man's apple" due to its low cost of production under varied soil and climatic conditions without much care. Spring (Ambe Bahar), rainy (Mrig Bahar), and autumn (Hasta Bahar) are the three separate flowering seasons in guava, with the corresponding harvesting times in the rainy, winter, and spring seasons (Rathore and Singh, 1974) [11] . The guava crop in the rainy season is rough, insipid, low in quality, and nutrition, and it is affected by a variety of insect pests and illnesses (Radha and Mathew, 2007). Therefore, Mrig bahar guava fruit matures during winter season is commercially taken. Since, guava could produce fruits throughout the year. Fruit matures during summer and rainy season are remains poor in quality and taste. Winter fruits are of higher quality, free of illnesses and pests, and command higher market prices. Winter crops have a longer storage life and can thus be transferred to destinations that pay well (Nautiyal et al., 2016) [8] . Guava tree bears flowers and fruits on the current season growth and flowers appear in the axils of new leaves, therefore it responds well to pruning. Unpruned guava trees tend to extend vegetative development, reduced bearing area, and eventually branch become unproductive. As a result, in order to control growth and to get fresh vegetative growth, pruning is beneficial practice in fruit crops (Jawadagi et al., 1996) [2] . Increase in the number of current season's shoots by pruning significantly influences productivity of the plant. Guava, being a current season bearing plant, responds favorably to different pruning practices. Shoot pruning increases the number of shoots in a newly pruned plant, which results in early blossoming and more blooms on current emergent branches, resulting in great amounts of flowers. Increasing the number of fruits improves the quality and output of guava, resulting in higher profits (Reddy, 2010) [12] . Pruning is the art and science of removing a section of a plant's development to improve its shape, vegetative growth, flowering, fruitfulness, and product quality. Shoot trimming is beneficial for reducing tree size and enhancing fruit quality, as well as increasing the number of trees per unit space.

Materials and Methods

The -3) and Shweta (CISHG-4) with four pruning intensity; 15 cm above portion of one/more year-old shoot (P 1 ), 30cm above portion of one/more year-old shoot (P 2 ), 45cm above portion of one/more year-old shoot (P 3 ), Control-No pruning (P 4 ). Different treatment combination is V 1 P 1: Lalit-15cm above portion of one/more year-old shoot, V 1 P 2: Lalit-30cm above portion of one/more year-old shoot, V 1 P 3: Lalit-45cm above portion of one/more year-old shoot,, V 1 P 4: Lalit-No pruning (Control), V 2 P 1: Shweta-15cm above portion of one/more year-old shoot, V 2 P 2: Shweta-30cm above portion of one/more year-old shoot, V 2 P 3: Shweta-45cm above portion of one/more year-old shoot and V 2 P 4 Shweta-No pruning (Control).

Results and Discussion

Vegetative parameters: The interaction between cultivars and pruning treatments was statistically found nonsignificant. However, the unpruned tree of both cvs. Shweta and Lalit (V 2 P 4 and V 1 P 4 ) expressed the highest tree height (5.93 m and 5.80 m, respectively) followed by pruned trees. and5.03 m 2 respectively. As a result, the interlinkage between the cultivars and pruning intensity were found statistically non-significant, the highest number of newly emerged shoot lets were found V 2 P 4 , i.e., interaction between the cv. Shweta and unpruned tree, recorded value was (5.66) and the lowest were found in V 2 P 1 i.e., interconnection between the cv. Shweta and 15 cm pruned shoot length. In cv. Shweta with 15 cm pruning level (V 2 P 1 ) shoot length was insignificantly larger (26.62 cm) than other interaction the lowest was outlined in V 1 P 4 i.e., unpruned trees of cv. Lalit (22.70 cm). The major shoot length was found in between the cv. Lalit and 15 cm pruned shoot length i.e., V 1 P 1 (0.35 cm) and lowest is found in interaction between cv. Lalit and 45 cm pruned shoot length i.e., V 1 P 3 (0.28 cm). The interaction between cultivars and pruning treatments was statistically found non-significant.

Whereas the unpruned tree of cv. Lalit (V 1 P 4 ) expressed the highest number of leaves (19.12) followed by 15cm pruned shoot length of cv. Shweta (V 2 P 1 ) and lowest was found in cv. Shweta and 30cm shoot length i.e., V 2 P 2 (17.18).Observations of leaf area revealed that there is an insignificant difference in leaf area between the interaction of cultivar and pruning treatments. The major leaf area was found in the interlinkage between the cv. Lalit and 30 cm shoot length pruning i.e., V 1 P 2 (57.29 cm 2 ) and lowest was recorded in cv. Shweta and unpruned tree i.e., V 2 P 4 (41.24 cm 2 ). Tree height showed non-significant among cultivars. However, cv. Lalit recorded the highest tree height than cv. Shweta. The highest tree height recorded in Lalit might be due to the genetic makeup of the variety which has vigorous growth habit. The tree height was significantly decreased with increasing the pruning intensity. Unpruned tree recorded significantly highest tree height than the pruned tree. Lesser height of pruned trees might be due to the fact that trees were unable to make up the loss of growth due to pruning in short period of time. Kumar and Rattan pal (2010) [3] also observed in guava that tree height reduced by removal of half of vegetative growth. Similar results obtained by Singh et al. (2012) [15] and Pratibha et al. (2013) [9] in guava

The stem diameter of tree trunks differed significantly due to treatments. The maximum stem diameter of tree trunk was noticed under cv. Lalit than cv. Shweta might be due the genetic makeup of the cultivar and climatic condition. Among the pruning effect, the major stem diameter in guava tree was observed under the highest pruning intensity (45 cm pruning level) and lowest in (15 cm pruned intensity). This may be due to the shift of metabolites from flowering sites to new vegetative growth sites influencing the increase in the stem circumference of the tree. This might be due to quick response to supplied food material absorbed by the roots and it transmitted to the main trunk of such trees. Moreover, in such trees most of the carbohydrates and nitrogen were utilized for the vegetative growth. These results are in concord with that Dhaliwal and Singh (2004) [14] in guava.

The cultivars and pruning treatments had an inconsiderable impact on canopy spread and canopy area. The data demonstrates that when the pruning acuteness increases it inversely affect the canopy spread. The maximum increase in canopy spread and canopy area found in cv. Lalit followed by cv. Shweta and canopy spread determined to be insignificant but canopy area found to be significant in the midest of cultivars. Canopy spread and canopy area was found to be significantly higher in unpruned trees than in all other pruned trees. The lowest value was found in pruning of 45cm shoot length. Lesser tree spread and canopy area in pruned trees might be due to the facts that trees were unable to make up the loss of growth due to pruning in short period of time. Analogous results have been reported by Kumar and Rattan pal (2010) [3] , Singh et al. (2012) [15] in guava.

The cultivars are counted non-significant difference, Shweta had more shoot lets (3.5) and Lalit had less (3.4) number of shoot lets. The fruit production is bound to increase with the increase in the number of new shoot lets produced, since the new shoots are the potent fruit bearing organs in guava the number of newly emerged shoot lets per twig was increased significantly but the unpruned branch showed highest number of shoot lets in severe pruning and minimum shoot lets found in light pruning. Shoot length has an insignificant variation in guava cultivars. Cultivar Shweta performed better shoot length. Among pruning level, unpruned trees recorded less shoot growth than pruned trees. Shoot length was found higher in pruned trees might be due to reserve food materials in main branches helpful to increase the length of new shoots which were emerged after pruning. Similar finding was also reported by Mohammed et al. (2006) [7] in guava that pruning at 60 cm resulted in maximum shoot length during rainy and winter season. Similar results have been reported by Meena et al. (2016) [4] in guava.

The effect of pruning treatments on the shoot diameter of new shoot lets revealed that amid the cultivars it showed the non-significant difference and the highest shoot diameter is recorded under the cv. Shweta (0.32 cm) and lowest is seen in cv. Lalit (0.31 cm). The 15 cm pruning level found highest shoot diameter and the lowest under control (unpruned). However, statistical analysis revealed that the other pruning treatments had a insignificant difference.

The number of leaves per shoot was found to be insignificant. The maximum leaves are counted in cv. Lalit may be due to the varietal character or more sunlight uptake.

Among the pruning treatment it showed the insignificant difference. Number of leaves found drastically decreasing whiles the pruning intensity increase. Due to longer shoot length in severe pruning, it consumes more nutrient so there is less availability of food for the leaves to emerge, hence the severe pruning had a smaller number of leaves and light pruning had a greater number of leaves.

Leaf area was insignificantly different among the cultivars and pruning treatments. The highest leaf area is recorded in cv. Shweta due to more interception of sunlight. Increased pruning severity resulted in a considerable reduction in leaf area. Leaf area was much larger in 15 cm shoot length pruning, while it was insignificantly lower in unpruned trees. The increased leaf area in pruning level than unpruned due to the creation of metabolites in pruned trees and as a result of increased availability of nutrients to these leaves.

Yield attributes:

The fruit weight interaction effect between cultivars and pruning intensity shown to be statistically insignificant. In comparison to all other interaction, the highest fruit weight (198.92 g) was reported between cv. Shweta with 15 cm pruning intensity (V 2 P 1 ) and the smallest fruit weight (134.64g) between unpruned Lalit trees (V 1 P 4 ). The highest fruit length outlined (9.34 cm) in V 2 P 1 i.e., cv. Shweta with 15cm pruning level and minimum outlined (5.07 cm) under unpruned Lalit trees (V 1 P 4 ). The interaction between cultivars and pruning treatments was statistically found non-significant. However, the unpruned tree of cv. Lalit (V 1 P 4 ) expressed the lowest fruit width (7.09 cm) and the highest fruit width (10.70 cm) was observed in cv. Shweta with 15cm pruning intensity (V 2 P 1 Fruit yield per tree and in a hectare was significantly affected by the cultivars, Lalit recorded higher yield may be appropriate to the inherited character of the variety. Maximum yield per tree was recorded from trees pruned 30 cm shoot length and lowest was recorded in unpruned trees. The fruit yield per tree and per hectare was also significantly affected by the pruning treatments. Bagchi et al. (2008) [1] reported a consistent increase in concentration of tryptophan, proline, polyphenol oxidase, catalase and peroxidase levels in leaves, bark and fruit of the guava tree and decreased in phenolics concentration after pruning. Such chemical changes, especially proline biosynthesis, in plants parts after pruning may have contributed towards more in flowering and fruiting, resulted in higher yield. On the basis of the results summarized above, it can be concluded that pruning was found most effective practice of guava to manage the tree canopy and crop regulation based upon positive results of effective management of plant growth parameters and vegetative character like tree height, stem diameter, spread, canopy area and number of shoot let. Maximum production and better quality of fruits was recorded in pruning intensity (30 cm pruning level). Whereas among cultivars, yield was better in cv. Lalit recorded more yield than Shweta but fruit size and fruit weight found higher in cv. Shweta. Conclusively, it emerges that shoot pruning of guava during summer (April-May) by the 30 cm pruning level was found most effective to manage plant growth factors and increased the growth, production and productivity of guava cultivars Lalit and Shweta.

References

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