Oil palm genetics may provide more reliable clues for ripeness
The research, undertaken by theMalaysian Palm Oil Board (MPOB) in conjunction with scientists from Orion Genomics, paves the way for increased production of palm oil - which accounts for 45% of the world's edible oil - and could also help to conserve sensitive wild habitats at risk of being turned into agricultural land.
Writing in the journal Nature Communications, the scientists identified a gene - known as the VIR gene - to be responsible for fruit colour changes in oil palm. Armed with this knowledge, the team identified that a rarely used variety known as virescens oil palm may provide producers with more reliable clues as to when fruits are ready to harvest.
"For more than four decades, Malaysian scientists have been collecting wild specimens of oil palm from across the globe, and without these materials, it is unlikely that we would have identified the VIR gene," explained Raviga Sambanthamurthi, PhD, director of MPOB's Advanced Biotechnology and Breeding Centre and lead author of the paper. "This collection, along with the recently completed genome sequence, is accelerating discoveries in oil palm genetics and epigenetics, and paving the way to increased productivity."
The guessing game
The team noted that currently, the majority of the oil palm fruit harvested in Malaysia and Indonesia is the nigrescens variety of fruit, which has black to deep purple skin that changes little when ripe.
However, Sambanthamurthi and colleagues noted that the virescens fruits change colour from green to bright orange when ripe - signalling the optimal time for harvesting.Such 'guess work' is a judgment call for harvesters to decide which bunch on any tree may be ready for harvest. Harvest fruit too early, and oil yields are significantly decreased. Overripe fruits yield lower quality oil as well.
Equiped with this new genetic knowledge of the oil palm and the VIR gene, the team suggest that palm growers can begin to replace nigrescens palms with virescens plants - which will eventually eliminate the need for harvesters to make a judgment call on over 20 billion bunches of oil palm fruit harvested annually.
This will increase the efficiency of the harvest and the oil yield from existing agricultural lands.
Even a 1% increase in Malaysian palm oil yield alone is worth in excess of RM 1 billion (USD 330 million) annually, said the team.
The authors documented five naturally occurring mutations in the VIR gene conferring the desirable trait were found in different populations of oil palm collected in Africa by Malaysian-government sponsored scientists during the last 40 years.
This identification of the VIR gene complements the same scientific team's earlier discovery of SHELL, a gene that studies published in Nature last year show leads to a palm fruit with oil yield up to 30% superior.
By combining the VIR and SHELL gene traits, breeders can develop palm lines that will further boost the efficiency of harvest and profoundly impact oil yield, they suggested.
"Feeding the world's growing population may be possible through the application of technologies to boost crop yields on existing agricultural lands," explained Robert A. Martienssen, Ph.D., co-author of the study, scientific co-founder of Orion Genomics.
"The identification of VIR and SHELL are just early steps. With the oil palm genome sequence in hand, thanks to decades of work by MPOB scientists, there is now tremendous potential to identify additional genes that increase yield for years to come."
Source: Nature Communications
Published online ahead of print, doi: 10.1038/ncomms5106
"The oil palm VIRESCENS gene controls fruit colour and encodes a R2R3-MYB"
Authors: Rajinder Singh, Eng-Ti Leslie Low, et al