polymorphism – Journal of Oil Palm Research

MOLECULAR CHARACTERISATION OF OIL PALM (Elaeis guineensis Jacq.) HYBRIDS

mpob_admin — Tue, 11 Jun 2024 06:51:10 +0000

For genetic mapping research in a crop like oil palm, polymorphic SSR (simple sequence repeat) markers are crucial. Thirty four SSR loci were used for screening in the current work to test a total of 10 hybrids at molecular level. There were between two and four alleles in these, with 22 of them being polymorphic and 12 being monomorphic. The primer SMG00026 had the greatest Polymorphism Information Content (PIC) value (0.60), while mEgCIR0408 had the lowest (0.14), with a mean PIC value of 0.22. Genetic variation scores varied between 0.15 (mEgCIR0408) and 0.66 (SMG00026), with an average of 0.286. Seven highly polymorphic markers, SMG00026, mEgCIR0074, mEgCIR0353, mEgCIR3350, mEgCIR0555, mEgCIR3886, and mEgCIR0905, were identified based on PIC and other genetic criteria. The oil palm crop development programme can effectively utilise the found polymorphic SSR loci in genetic diversity investigations and mapping. The 10 hybrids were divided into two primary clusters by a total of 22 polymorphic SSRs, and the observed clustering was based on geographic origin. These polymorphic primers can be used effectively because they make it easier to choose promising varieties at nursery stage, which helps both researchers and farmers to modernise the plant breeding programme for oil palm.

ISOENZYME VARIATION OF ZAIREAN OIL PALM (Elaeis guineensis Jacq.) GERMPLASM COLLECTION

mpob_admin — Tue, 16 Nov 2021 16:11:18 +0000

Genetic variation was studied in a Zairean oil palm germplasm collection by employing native polyacrylamide gel electrophoresis of isoenzymes. Three isoenzymes extracted from leaves, namely superoxide dismutase (SOD), peroxidase (PRX) and glutamate dehydrogenase (GDH) were investigated. Polymorphism was detected in SOD and PRX systems but there was no genetic variation in GDH system. Polymorphic indices obtained from SOD and PRX systems revealed that the degree of polymorphism increased from the family to the ecotype level. This study also showed that the degree of polymorphism is influenced climatically and geographically.

GENETIC CONTROL OF POLYMORPHISM FOR KERNEL-TO-FRUIT RATIO IN THE OIL PALM (ELAEIS GUINEENSIS JACQ.)

mpob_admin — Fri, 26 Mar 2021 07:39:33 +0000

A study to clarify the genetic control of polymorphism in kernel-to-fruit ratio in the oil palm Elaeis guineensis Jacq. was carried out on the basis of the following crosses from the NIFOR oil palm breeding programme – 45 tenera (T) x tenera; 24 tenera (T) selfings; 33 dura (D) x tenera; and 29 tenera (T) x dura (D).

The mean kernel-to-fruit ratio (%K/F) for the dura and tenera fruit forms and the tenera:dura (T:D) ratio of %K/F were determined for each of the segregating progenies. Estimates of correlation coefficient (r) and narrow-sense heritability (h²) derived from parent-offspring regression analysis for the T:D ratio of %K/F were obtained for each type of cross. Dura and tenera fruit forms showed distinct differences in their mean %K/F, thus confirming that the oil palm exhibits polymorphisms in its kernel size, with the dura progeny having a higher mean %K/F than the tenera in all the segregating crosses.

The coefficient of correlation between the %K/F of the tenera parent and the tenera:dura ratio of %K/F of selfed offspring was highly significant (r = 0.52**). The comparison between the female tenera parent T:D ratio of %K/F and that of the TxT offspring was highly significant (r= 0,44**) with a high narrow-sense heritability estimate (h² = 67%). A similar comparison with the male tenera parent was not significant (r = 0.18NS) and had a low heritability estimate (h² = 25%). In DxT and TxD crosses the estimates of the correlation coefficient of the tenera parent to T:D ratio of %K/F and the offspring values were not significant (r = 0.17NS and 0.20NS respectively).

This indicated that tenera parents carry a certain kernel inhibiting factor (or factors) that reduces the kernel size of the tenera offspring relative to their dura sibs. This factor(s) was transmitted to the tenera offspring especially when tenera was the female parent. The kernel in-hibiting factor(s) is proposed to be closely linked with the recessive allele of the gene controlling shell thickness. The implication of this for the kernel size and fertility of pisifera palms is discussed.

X-RAY DIFFRACTION ANALYSIS OF PRODUCTS OBTAINED BY DRY FRACTIONATION OF PALM OIL

mpob_admin — Sat, 13 Mar 2021 16:18:40 +0000

Palm oil was dry fractionated by four different methods, namely (1) cooling at 30ºC and (2) at 23ºC for 18 hours with no agitation, (3) cooling at 3ºC for 18 hours with agitation and (4) at 22ºC for 3 hours with agitation. The yields of stearin were 16%, 30%, 26% and 32% respectively. Filtration rates were good when fractionation took place with no agitation but were poorer with agitation. X-ray analysis showed the stearins from methods 1, 2 and 4 to be in the beta-prime form while that from method 3 was in the beta form. These polymorphic forms were stable when the stearins were stored up to 12 days. When the stearins from methods 1 and 2 were tempered at 40º and 45ºC the polymorphic form changed to the beta form. When melted and then crystallized at 0ºC all the stearins crystallized in the beta-prime form. A hydrogenated palm oil crystallized in the alpha form under these conditions.

The short spacing of the beta-prime form of palm oil and palm products is unique in that it shows two distinct lines of strong intensity at 0.43 and 0.41 nm as opposed to one at 0.42 nm reported in other fats. The softening points of the stearins correlated with the C48 triglyceride content but the dropping points did not.