Effet de la durée de conservation sur la qualité du pollen en production de semences chez le cocotier (<i>Cocos nucifera</i> L.)

Abstract

RésuméLes présents travaux visent à proposer des voies d'optimisation du rendement de la production de semences par fécondation contrôlée chez le cocotier. Les variétés de cocotier Grand de Comores (GCO) et Nain Jaune de Malaisie (NJM) ont été utilisés à cet effet. Le pollen produit à partir de l'inflorescence est conditionné sous vide et conservé au congélateur à -15°C pendant 4 mois. Chaque mois, la qualité du pollen est évaluée. Il ressort que GCO fournit par inflorescence 8,6 g de pollen et NJM, 5,7 g. Pendant la conservation les taux de nouaison diminuent en général de 20,5 à 1,1 % après 4 mois. Les teneurs en protéines et en sucres non réducteurs diminuent respectivement de 30 à 7,1 % et de 7,9 à 2,3 % alors que celles des sucres réducteurs augmentent de 0,7 à 1,1 %. La qualité du pollen conservé au delà de 1 mois est donc altérée et affecte le rendement de la production de semences. Mots clés:Cocotier, fécondation contrôlée, qualité du pollen, conservation. CMT and MYD produced 8.6 g and 5.7 Abstract Effect of the storage time on the quality of pollen in the seeds production at the coconut palm (Cocos nucifera L.). The main objective of this study is to find the ways to optimize the yield of controlled pollination in the coconut palm. Pollen from the coconut varieties Comoro Moheli Tall (CMT) and the Malayan Yellow Dwarf (MYD) stored in deepfreezer for 4 months at -15°C is studied. This study shows that

Typology in the fertility of seven Tall coconut (Cocos nucifera L.) populations using artificial pollination traits in field genebank

“…The markers such as the rate of in vitro germinating pollen and the weight of pollen per inflorescence that do not appear in the coconut conventional descriptors listed by the IPGRI (1995) were very discriminative. Similar results were previously mentioned by Yao et al (2010) from both natural ''Tall'' and ''Dwarf'' coconut ecotypes. However, the rate of seeds germination could be deleted while measuring the breeding performance in controlled pollination of any coconut accession.…”

“…The practice requires the contribution of the pollen produced from interesting male coconut parental on the mature female flowers of seed-bearing trees in isolated condition using pollination jute-bags. Otherwise, the coconut records a low rate of breeding since 20-30 nuts.tree -1 and 0-4 nuts.tree -1 are yearly produced in respective natural and controlled pollinations (De Nucé et al, 1980;Yao et al, 2010). This low rate of reproduction delays the regeneration achievements and increases the financial costs involved.…”

“…Previous attempts on the controlled pollination have been achieved regarding the setting of pollination method (De Nucé et al, 1980), and the extraction and preservation of the pollen (Rognon and De Nuce, 1978). Hence, Yoboue (2009) and Yao et al (2010) respectively revealed that the isolating inflorescence bag and the pollen's quality result in significant effects upon the success of the controlled pollinations. Yet, there's scanty survey delivered specifically for the regenerative performance in controlled pollination of a high number of coconut ecotypes.…”

“…Then, the pollen was extracted using the process drawn by Rognon and De Nucé (1978) and the full pollen gathered from each inflorescence was weighed (IWP) using a two-digit scale. For the determination of the rate of pollen in vitro germination (RPG), 0.25 g of pollen was plated in solid media plates prepared with agar, sucrose and distilled water (Yao et al, 2010). The number of germinated or not germinated grains of pollen was observed under Light Microscope (LM) equipped of a camera VC 3011 at 100x magnification (Yao et al, 2017).…”

“…The number of germinated or not germinated grains of pollen was observed under Light Microscope (LM) equipped of a camera VC 3011 at 100x magnification (Yao et al, 2017). A grain of pollen has germinated when its diameter was inferior or equal to the length of the pollen tract (Yao et al, 2010). Assessment of the fertility in coconut female parental plants: At the field, two (2) to four (4) female parental coconuts were randomly selected per accession and fertilized with the pollen collected from the male parental chosen within the same Tall coconut population according to the method suggested by De Nuce et al (1980).…”