Varietal difference in mango for phenological responses under Konkan condition

Introduction

Konkan region in west coast of India is known worldwide for commercial cultivation of prime Indian export mango variety "Alphonso". Red lateritic, slightly acidic soil with annual rainfall ranging from 3000-3500 mm during June to September, followed by bright sunny days period of over 7 months from October to May, render this region as one of the best regions in the world for commercial cultivation of mango (Burondkar et al. 2012) [1] . In this region, mango is cultivated in an area of 1,03,960 ha. Which is about 10 per cent of the total area under mango in the country. However, the productivity of mango in Konkan is about 2.69 t/ha., which is about three times less than the average productivity of the country (Anon., 2019 d) [2] . During recent years, climatic conditions in Konkan region are experiencing drastic changes such as unseasonal rains especially during flowering and fruit development, delayed monsoon, prevalence of low temperature (<17˚c) for prolonged periods and sudden rise in maximum temperature during February-March. These climatic events made greater influence on phenology in mango which resulted in an extended profound efect on vegetative growth immediately after harvest, irregular flowering, severe fruit drop due to temperature variation etc. However, the work pertaining to the efect of seasonal variation on physiological behaviour leading to biochemical changes associated with growth and yield of diferent mango varieties viz. Alphonso, Kesar, Ratna, Amrapali and Tommy Atkins are very meager hence the present study on "Varietal diference in mango for physiological responses under Konkan condition."

Material and Methods

Location and plant material: The experiment was conducted during 2019-2020 with an objective to study the weather association with phenology of diferent mango cultivars in Konkan. Field experiment was conducted in plot No. 9,11,12 and centre of excellence on 25 trees at College of Horticulture, Dapoli. Healthy and vigorous 25-30 years old plants were selected for the present studies, adopting randomized block design. Scale: Developmental stages and morphological characteristics were recorded as per BBCH scale.

Representative shoot parts were coded as per primary and secondary phenological growth stages and photographed for recorded information. Due to inclusion of the mesostages between the principal and secondary growth stages, three digit scale was used to study the mango phenology. The existing BBCH scale (Hernández et al., 2010) [3] was used for the entire developmental cycle of mango and was subdivided into seven clearly recognisable and distinguishable principal growth stages out of 10 of general BBCH scale. Each principal growth stage was classified into secondary stages which described points in time or shorter developmental intervals in the major growth stage. This scale started with bud development (stage 0) and terminated at maturity of fruit (stage 8). The secondary stages were numbered 0 to 9 that described related percentile stages of growth. Several mesostages (1 to n) were used to describe the diferent vegetative and floral flushes during season for coding bud, leaf and shoot development. A list of phenological stages of mango, made in ascending order by sorting codes into numerical order and A photo guide (Fig. 1) with codes was developed and used for uniform data recording at diferent cultivars.

Results and Discussion

Phenological stages of diferent mango cultivars were given in Table 1 and depicted in Plate 2, 3, 4, 5 and 6. It was observed that, the bud emergence phase started with stage 011 i.e. beginning of leaf bud swelling, bud scales begin to separate, which was observed early in Alphonso mango during 2 nd week of August, Tommy Atkins during 3 ^ rd week of August, Kesar during 2 nd week of September, Ratna during 3 ^ rd week of September and late in Amrapali during 2 nd week of October. Bud emergence phase stopped with stage 019 i.e. Bud break: light green to dark coppery tan leaf tips, visible 5 to 10 mm above bud scales which was completed faster in Alphonso during 4 th week of September, in Tommy Atkins and Kesar during 1 st week of October, Ratna during 2 nd of October and late in Amrapali during 1 st week of November.

The leaf development phase started with stage 110 i.e. leaf tips more than 10 mm above bud scales, this was observed early in Alphonso during 1 st week of October, in Tommy Atkins and Kesar during 2 nd week of October, in Ratna during 3 ^ rd week of October and late in Amrapali during 2 nd week of November. The leaf development phase ended with stage 119 i.e. all leaves completely unfolded and expanded which was completed earlier in Alphonso during 1 st week of November, in Kesar and Ratna during 2 st week of November, in Tommy Atkins during 3 ^ rd week of November and late in Amrapali during 1 st week of December. The shoot development phase started with stage 311 i.e. beginning of shoot growth axes of developing shoots visible about 10% of final length, this was observed in Alphonso during 2 nd week of November, Kesar and Ratna during 3 ^ rd week of November, in Tommy Atkins during 4 th week of November and late in Amrapali during 2 nd week of December; whereas shoot development phase ended with stage 319 i.e. Shoots about 90% of final length which was completed earlier in Alphonso during 3 ^ rd week of December, Tommy Atkins during 4 th week of January, Kesar during 1 st week of February, Ratna during 4 th week of February and late in Amrapali in 3 ^ rd week of March. The inflorescence emergences phase started with stage 511 i.e. beginning of bud swelling: scales begin to separate, this was observed early in Alphonso during 4 th week of December, Tommy Atkins during 1 st week of February, Kesar during 2 nd week of February, Ratna during 1 st week of March and late in Amrapali during 4 th week of March whereas inflorescence emergences phase end with stage 519 i.e. End of panicle development: fully developed secondary axes, many flowers with green to crimson petal tips visible and some opened. Leaves fully developed in case of mixed panicles which was completed earlier in Alphonso mango during 1 st week of February, Tommy Atkins during 3 ^ rd week of February, Kesar during 1 st week of March; Ratna during 3 ^ rd week of March and late in Amrapali during 1 st week of April. [4] .

The flowering emergences phase started with stage 610 i.e. Data revealed that the earliest emergence of bud phase, vegetative flush, flowering, fruiting stage and harvesting was observed in cultivar Alphonso, followed by Tommy Atkins, Kesar and Ratna; however, the late emergence of bud phase, vegetative flush, flowering and fruiting stage was observed in Amrapali. The days required for maturation of mango cultivars viz. Alphonso, Kesar and Ratna fruits showed diferent periods due to the heat units requirement. Alphonso fruits mature early than Kesar and Ratna due to smaller fruit size and requirement of less heat units than other varieties (Shinde et al., 2001) [5] location diferences in phenological behaviour in mango are widely reported. [4] .

Phenological characteristics of different mango cultivars

Phenological studies aim on the periodicity in the life-cycle events of plants are influenced by seasonal variations owing to weather factors mainly temperature and precipitation. In fact, changes in the time of phenophases of fruit trees are of great economical importance because they have direct impact on factors influencing final fruit yield (Kushwaha and Singh, 2008) [6] . Phenological studies in mango are also important for planned management of orchards and alerting mango cropping against environmental conditions. It is also useful for understanding the phenological impacts during the flowering phase which is the most sensitive and yield determining phenophase. Under Konkan conditions, mango plant should give new vegetative flush (as an apparatus for photosynthesis) immediately after harvest of crop in May or at least on the onset of monsoon in June in order to rebuild the CHO stock, depleted with the harvest of previous seasons fruit yield. This flush should get physiologically matured in next four months by the end of September and remains dormant for next 3-4 months to have maximum accumulation of moveable reserve carbohydrate needed subsequently for resumption of reproductive phase by the end of November -December followed by flowering and fruiting towards the end of May, thus completing all the three phenophases (vegetative growth, quiescent and reproductive phage) in single calendar year (Burondkar et al., 2018) [7] .

In the present experiment, data revealed that earliest emergence of bud phase, vegetative flush, flowering, fruiting stage and harvesting was observed in cultivar Alphonso, followed by Tommy Atkins, Kesar and Ratna; however, the late emergence of bud phase, vegetative flush, flowering and fruiting stage was observed in Amrapali. The days required for maturation of mango cultivars viz. Alphonso, Kesar and Ratna fruits showed diferent periods due to the heat units requirement. Alphonso fruits mature early than Kesar and Ratna due to smaller fruit size and requirement of less heat units than other varieties (Shinde et al., 2001) [5] location diferences in phenological behaviour in mango are widely reported. Alphonso reported to put forth 3 to 4 vegetative flushes, generally in the month of January, February, September and November respectively (Patil, 1999) [8] . In the Konkan region, vegetative flush during October-November i.e. immediately after rainy season is major and very common. The large extent of this vegetative flush decides the fate of the mango crop in a particular year. In fact, occurrence of this flush considered untimely as it does more harm than good, as far as initiation of FBD or flowering is considered, particularly in Cv. Alphonso (Rao, 1981) [9] . Chandra et al., (2001) [10] reported early flowering in Prabhashankar, Arka Puneet, Mallika and Alphonso. They further observed early panicle emergence in Kesar, Bombai, Banglora, Baneshan, Langra and Mallika under Sabour (Bihar) condition. Yadav and Singh, (1995) [11] reported that South Indian varieties showed earlier emergence of panicles compared to those of North Indian varieties. [4] . [4] Conclusion Alphonso had early vegetative flush emergence stage (115-319), flowering stage (611-630) and fruit development stage (701-809) followed by Tommy Atkins and Kesar. However, all these stages were delayed on Ratna and late on Amrapali. The maturity stage (800-809) for harvest was achieved early by Tommy Atkins followed by Alphonso. However, Kesar and Ratna had matured late followed last by Amrapali.

References

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