Tanzania Virescent and Early Evaluation of Their Descendant

The Tanzania oil palm population was introduced to Sumatra Bioscience (SumBio)-PT PP London Sumatra Indonesia Tbk, when two palms of open-pollinated seeds were planted at Bah Lias Estate in 1996. One of two palms was confirmed as virescent dura after producing bunches. The virescent dura was selfed, and F1 progeny were planted in 2001. Bunch character data shows that the F1 progeny of Tanzania virescent dura had a large kernel size with a kernel-to-bunch ratio (KB) of about 8%. On the other hand, the segregation of F1 progeny shows 87% of descendants are virescent. Three virescent dura had offspring with 100% virescent bunches in the F2 generation, and the progenies have a mean KB ratio higher than their grandparents by about > 8,6%. Fortunately, the molecular marker analysis carried out on F1 progeny confirmed that those three dura palms were homozygous virescent. The F1 homozygous virescent duras were tested with selected elite pisifera planted in the progeny trial in 2019. Early recordings showed that all DxP progenies derived from Tanzania homozygous virescent were 100% virescent. Preliminary evaluation based on bunch and oil analysis results showed the combination between Tanzania virescent homozygous dura and Ekona pisifera gave progeny with an increasing KB ratio compared to their parents, around 13.5%. Unfortunately, it has a lower oil-to-bunch (OB) ratio (23.1%). A combination of Tanzania virescent and Binga gave progeny with a slight increase in the KB ratio of about 11.2%, but the OB ratio is better at around 24.5%. According to these preliminary findings, Tanzania virescent passes on high KB characteristics to its progeny. In the next few years, yield and growth records will continue to be carried out to see the consistency of the characters possessed by each cross combination with the unique virescent bunches to indicate bunch ripeness.


Introduction
The exploration of oil palm genetic resources is being carried out to obtain unique characteristic.The aim is to improve crop productivity and harvest efficiency.One of the unique characteristics of oil palm that has been developed is virescent.
Virescent is an uncommon fruit color [1], characterized by a green-violet color when the fruit is unripe and changes color to orange-reddish when ripe [2].The dramatic change in fruit color from unripe to ripe adds interest to the virescent character since it makes it simpler to recognize ripe fruit without having to wait for the fruit to detach [3].As a result, the color of the virescent fruit characteristic changes, serving as a gauge of the bunch ripeness.Genetically, oil palm with virescent fruit is governed by the virescent (VIR) gene [4].Based on this information, BLRS designed an SNP marker from the five independent mutant alleles of the VIR gene and denote the mutation as the Wt (wild type) and mutation events 1 to 4, respectively.Through this approach, we intend to perform an early selection of the homozygous or heterozygous virescents oil palm at the nursery stage, which allows Breeders to develop homozygous virescent for further breeding programs.
PT PP London Sumatra Indonesia, Tbk.'s research and development division, Sumatra Bioscience at Bah Lias Research Station has a collection of oil palm virescent from several Population, and one of them comes from Tanzania.The Tanzania population was introduced to SumBio when two openpollinated seeds were planted at Bah Lias Estate in 1996.One of the two palms was confirmed as virescent dura after producing bunches.Molecular marker analysis conducted by Sumatra Bioscience's Genomic Laboratory on the F1 progeny Tanzania dura virsecens confirmed that the three dura palms were homozygous virescent.Tanzania itself is one of the origins of the virescent oil palm.Richardson and Chavez [5] reported that they had obtained virescent material from a progeny collected from the Kwitanga area in Western Tanzania by Blaak in 1977.During a journey to Tanzania in 1986, the expedition team discovered dense palm groves with a frequency of roughly 90% dura material and the remaining being Tenera, where 10% of the bunches were virescent.[6].Moreover, the germplasm samples analyzed to obtain the VIR gene partially came from Tanzania origin [4].This paper will describe the performance of Sumatra Bioscience's Tanzania dura virescent and the early evaluation of DxP progeny derived from dura homozygous virescent.

Materials and Method
The virescent dura palm of Tanzania was selfed, and its descendants were planted in formal experiments in 2001 and had offspring that were 87% virescent.The F2 generation was planted in 2016 and produced offspring with 100% virescent.Three Tanzania dura homozygous virescent were selected and crossed with elite pisifera planted in 2019 to assess the performance of the DxP progenies.The experiment was set up with an alpha design that included four replicates of 20 DxP progenies, five blocks per replicate, and one block consisting of four plots with 16 palms on each plot.Yield measurements were recorded using methodologies described by Breure and Verdooren [7].A sample of individual bunches from each progeny was analyzed using the methods described by Blaak, et al. [8] and Rao, et al. [9].

Results and Discussion
The yield performance of Tanzania virescent F1 progeny is shown in Table 1.The trial was planted in 2001.As a dura material, the yield of the Tanzania population over five years of production in terms of fresh fruit bunch yield (FFB) and oil and kernel yield (OKY) is the lowest compared to other populations, particularly when compared to Deli x AVROS, which are DxP materials.Fruit color census in two progenies of Tanzania materials reveals that 95 out of 109 palms (87%) are virescent, while 18 other palms cannot be identified because they do not produce bunches.As it is known that the oil-to-bunch (OB) in dura material is low, so does that of Tanzania dura material which shows an OB value of around 17%.However, it has a reasonably high KB value of around 8%.It is in line with information from Khusairi et al. [10], who reported that the Tanzania dura material, which is a collection of MPOB germplasm has an OB ratio of around 13.9% and a KB ratio of around 8.4%.
Screening on F1 Tanzania dura virescent materials using BLRS SNP markers obtained three homozygous Tanzania dura virescent.The self-progeny Tanzania dura virescent are homozygous were planted into the field in 2016.
The yield performance and bunch characteristics of the Tanzania F2 progeny can be seen in Table 2.With the except for two palms that have not yet produced any fruit bunches and whose fruit color is still unknown, a fruit color census of Tanzanian progenies showed that all dura selfs possessed the virescent trait at 100%.Over three years of production, the F2 progeny of Tanzania dura produced a slightly lower FFB yield than the trial mean but was comparable to standard DxD crosses.The size of the bunches in the Tanzania dura material is heavier than other dura progeny, but it has a few numbers of bunches, which causes a low FFB yield.
Bunch character data shows the F2 progeny of Tanzania virescent dura had a high KB of around 8.6%, which is an increase from their parents.Compared to the other dura progenies, the kernel weight of Tanzania dura is the heaviest.Unfortunately, the low mesocarp-to-fruit (MF) ratio in the Tanzania dura material (< 45%) has an impact on the lower oil-to-wet mesocarp (OWM), which results in a lower OB ratio.
Tanzania dura virescent homozygous crossed with elite Pisifera was tested as part of a DxP progeny testing trial 2019.Yield production in the first year for each breeding material is shown in Table 3.The DxP progenies derived from Tanzania dura virescent homozygous gave FFB yields as good as comparison material Deli x AVROS in the first year of production.Likewise, the OKY value is relatively similar, particularly for Tanzania x Binga and Tanzania x AVROS materials.The fruit color census in all DxP progenies of Tanzania dura virescent homozygous has produced 100% virescent.
The results of the bunch character analysis are shown in Table 4. Bunch sampling was carried out on early mature palms.The analysis results showed that the DxP progeny of Tanzania dura as the female parent had a higher KB ratio than other populations.This character is inherited from their female parent.The high KB is supported by the heavier kernel (KW) and nut (NW) as well as more giant shell-to-fruit (SF) and kernel-to-fruit (KF) ratios.The large kernel size and the increased ratio of SF impact thinner mesocarp (MF).A lower MF ratio causes the oil content in the wet mesocarp (OWM) to be lower as well, which harms the OB value.Tanzania dura x Ekona pisifera materials had the highest KB ratio of 13.5%.The combination of both parents with high KB traits, produces DxP offspring with outstanding KB values.The distribution of the KB ratio over progeny for each breeding material can be seen in Figure 1.Conversely, Tanzania x AVROS and Tanzania x Binga crosses produce DxP progenies with a better OB ratio of around 24,5%, which is higher than other Tanzania crosses.The observation of the progeny testing trials will be continued in the next few years to see the performance of the tested breeding materials.

Conclusion
During the first year of production, the DxP progeny derived from Tanzanian dura virescent had an FFB yield and total palm product (OKY) as good as the Deli x AVROS material, especially for the Tanzania x AVROS and Tanzania x Binga crosses.DxP progeny derived from Tanzanian dura virescent homozygous has a large kernel size and a high KB ratio inherited from the female parent.The DxP progeny of the Tanzania dura homozygous are 100% virescent.Observations on the progeny testing trial will be continued in the next few years.These preliminary results provide optimism for obtaining a new material with high yield potential and unique virescent characteristics that can be used to indicate bunch ripeness in the future.

Table 1 .
Performance of Tanzania progenies and other populations planted in 2001.

Table 2 .
Yield performance and bunch characteristic of Tanzania F2 dura and other dura progenies planted in 2016.

Table 3 .
First-year yield performance of each DxP progeny trial planted in 2019.

Table 4 .
Bunch Characteristics of DxP Progeny Trial Planted in 2019.