Browsing by Author "Vinu K. Cherian"

Now showing 1 - 7 of 7
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    Gas exchange parameters and canopy area in relation to coconut productivity in two agroclimatic regions of India
    (2008-01) Siju Thomas, T.; Naresh Kumar, S.; Vinu K. Cherian; Rajagopal, V.
    Coconut (Cocos nucifera L.) palms exhibit variation in productivity across different agro-climatic regions of India. It is important to study the factors contributing to such variation in order to increase the productivity of palms. The present study was intended to elucidate the physiological basis of yield variability in coconut across different agro-climatic regions. With this objective, seasonal variations in leaf gas exchange parameters and morphological and dry matter production characteristics of four coconut cultivars were studied at two different agro-climatic regions. Results indicated variation in gas exchange parameters of cultivars with seasons and with regions suggesting genotype-environment interactions. Overall net photosynthetic rates were higher in cultivars grown at Western ghats-hot sub humid per humid region (Kidu). Palms growing at Eastern coastal plains-hot sub humid region (Veppankulam), on the other hand, maintain greater water use efficiency. The results also indicate that, under dry conditions both stomatal and non-stomatal factors impose limitations to photosynthesis in coconut. The physiological efficiency coupled with superior morphological characters such as a larger canopy, and favourable climatic conditions for a longer period, in addition to the soil type at Veppankulam region enabled the palms to attain more of their potential productivity.
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    Identification and Characterization of in Situ Drought Tolerant Palms in Farmers Fields in Different Agro-Climatic Zones
    (2002) Naresh Kumar, S.; Rajagopal, V.; Siju Thomas, T.; Vinu K. Cherian; Hanumathappa, M.; Anil Kumar; Srinivasulu, B.; Nagvekar, D.
    Coconut palms are mainly grown as rainfed crop, and are exposed to drought of different intensities and durations in various parts of the country. It is important to identify and conserve the ecotypes, which could withstand the vagaries of nature and still performed better in terms of growth and yield. Such efforts will ensure that the natural genetic variability and desirable traits are identified and conserved for further exploitation. With this in view present survey was undertaken in farmers fields at different agro-climatic zones, viz., Western coastal area - hot sub-humid-per-humid (Ratnagiri - Maharastra), hot semi arid (Arisikere - Karnataka) and Eastern coastal plains- hot sub-humid (Ambajipeta- Andhra Pradesh), which represent the major coconut growing areas in India. These places faced periodical durought during last 15 years and the dry spell was longer in Ratnagiri (216 days) and Arsikere (202 days). During survey drought affected and apparently tolerant palms were selected based on morphology. The data indicate that in situ drought tolerant palms had more number of leaves, bunch and mature nuts compared to the affected palms. Gas exchange characters were also high in apparently tolerant palms. These palms also exhibited good water use efficiency. However, the biochemical composition did not show any definite trend between tolerant and susceptible types. The superiority of these palms in the photosynthetic parameters showed their capacity for drought tolerance and high yield. The tolerant palms can be used as mother palms in breeding programme for drought tolerance.
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    Role of certain biochemical compounds in adaptation of coconut to different weather conditions - A study in two agro-climatic regions of India
    (2006-03) Siju Thomas, T.; Naresh Kumar, S.; Vinu K. Cherian; Kasturi Bai, K.V.; Rajagopal, V.
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    Stability Analysis For Dry Matter Production And Yield Components Of Coconut In Two Agroclimatic Regions Of India
    (2005) Siju Thomas, T.; Rajagopal, V.; Naresh Kumar, S.; Arunachalam, V.; Vinu K. Cherian
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    Variations in nut yield of coconut and dry spell in different agro-climatic zones of lndia
    (2007-09) Naresh Kumar, S.; Rajagopal, V.; Siju Thomas, T.; Vinu K. Cherian; Ratheesh Narayanan, M.K.; Ananda, K.S.; Nagawekar, D.D.; Hanumanthappa, M.; Vincent, S.; Srinivasulu, B.
    Coconut is the major perennial crop in coastal areas of lndia. It is mainly grown under rainfed conditions in areas of high rainfall. However, these plantations face summer drought situations as the rainfall distribution is restricted to only 4 to 5 months a year, leaving remaining period as dry. The objective of the study is to quantify the dry spell and to deduce the influence of rainfall and dry spell on the nut yield in major coconut growing areas situated in different agro-climatic zones of India. viz., western coastal area - hot sub-humid per-humid (represented by Kasaragod in Kerala and Ratnagiri in Maharashtra), Western Ghats - hot sub-humid per-humid (represented by Kidu in Karnataka); hot semi-arid (represented by Arsikere in Karnataka); and eastern coastal plains - hot subhumid (represented by Veppankulam in Tamil Nadu and Ambajipeta in Andhra Pradesh). Variation in annual rainfall was from a maximum of 3337.7 mm (Kasaragod) to a minimum of 718.23 mm (Arsikere). Dry spell was longer in Ratnagiri (216 days) and Arsikere (202 days), and shorter at Kidu (146 days). The annual nut yield under rainfed conditions varied from 68 (Ambajipeta) and 66 (Kasaragod) to 41 (Arisekere) and 30 (Kidu). Impact of variations in dry spell on nut yield was discernible from the study. In view of the long duration (44 months) between the inflorescence initiation to nut maturation, the occurrence of dry spell in any one year would affect the yield for the subsequent three to four years. It can be inferred that the longer dry spell affects the nut yield for next four years to follow with stronger impact on fourth year, irrespective of the total rainfall.