Coconut Breeding in Indonesia — II The Yield Potential of Improved Varieties of Coconut

The analyses of yield data collected from 986 progenies of Indonesian Tall X Indonesian Tall showed their high production capability: 123 nuts/32.29 kg copra per palm/yr. Six of them produced 168 nuts/58.11 kg copra per palm/yr. Two families showed general combining ability and no inbreeding depression. They will be very useful for breeding for high yield of copra.


INTRODUCTION
High-yielding mother palms of Indonesian Tall (IT) (Cocos nucifera, var typica, form typica) have been selected by P. M. L. Tammes from coconut groves in the village gardens near Manado, North Sulawesi Indonesia.He planted their open-pollinated progenies in 1926 and 1927 at the Coconut Experimental Station, Mapanget, North Sula wesi (Tammes, 1958).This constitutes the first generation of palms.Subsequently, A .F. Innes used the Mapanget population for a crossing programme and planted the progenies between 1957 and 1959 at Kima Atas Experimental Station, near Manado, North Sulawesi-the second generation.
A large number of palms are dead.H. Soedasrip and T. Toar at the Manado Branch of the Lembaga Penelitian Tanaman Industry have collected whatever data avai lable regarding the Kima Atas population of palms and re-constructed the layout of the trials and the numbering of the palms.The results presented in this paper are based on these records.Further, it is a continuation of the series.Coconut Breeding in Indonesia-1 (Liyanage,etal 198.6).
The climatic conditions at Kima Atas are satisfactory for coconut cultivation.The soil Is fertile being of volcanic origin.The plantation has been neglected over the years until management practices with application of NPK fertilizer were introduced in 1975.

Numbering of palms
The system of numbering of palms adapted by Tammes in the Mapanget population is unique, eg 32 g 11, 83 f IV, etc. 32 g II : represents seedling number g derived from mother pabn number 32 and planted in block number 11.
83 f IV : similarly, seedling/from mother 83 planted in block IV.

Material
The Kima Atas population is composed on 11 field trials covering 986 palms (Appendix 1).The trials are as follows: TrialsA

Method of recording
Yield records of the 986 palms at Kima Atas were kept from August 1975 to July 1977.Data recorded at each pick were number of bunches, number of nuts and weight of husked-nuts.Six picks were harvested each year at bimonthly intervals.A sample of 5 husked-nuts taken at random from each pick was weighed.The total weight of husked-nuts at each pick per palm was calculated on the basis of the sample weight.Then 100 husked-nuts taken at random from each trial was weighed and turned into copra.The relationship between husked-nuts and weight of copra was 26 per cent.This ratio was used to convert husked-nut weight into copra.
Prior to commencement of yield recording, it was reported that there was consider able theft of nuts at Kima Atas.In order to reduce the error in yield data due to the loss of nuts, the following procedure was adapted.
Prior to the first yield recording, the bunches on the crown of each palm were num bered serially 1, 2, 3 beginning with the oldest bunch and ending with the in florescence just open.Then the number of fruits/female flowers on each bunch was recorded and was continued at six-monthly intervals.
If there was a loss of nuts or bunches from any palm, an adjustment in the yield data of that palm was made as follows.Say, the bunch marked 10 has been removed.The number of female flowers borne on that bunch is available.The mean percentage of female flowers developed into fruits of the 9th and 11th bunches was calculated and the number of fruits on the 10th bunch was estimated on that basis.The weight of huskednuts was also recorded on a similar basis.Fortunately as loss of nuts was negligible, it was not necessary to apply this formula.

Statistical analyses
The field trials have been planted in a randomized lay:-out, presumably with an equal number of progenies per treatment.However, due to the neglect of the plantation, a number of palms are dead resulting in fewer than four progenies in some treatments.Consequently statistical analyses was done on a full randomization basis.The statistical analyses was restricted to yield of copra, as it is the most important economic character of the palm.Statistical significance is indicated in the following pages as significant at P=0.05, **significant at P -0.01, ***significant at P 0.001, /i.v = denotes not significant.

RESULTS
The summary of data collected for the two years 1975/76 and 1976/77 is presented in Table 1 The analysis of variance done for each trial separately with respect to copra produc tion, showed that there were significant differences between treatments only in 5 out of 11 They are Generally, the out-crossed progenies are superior to those of sib matings.There are two field trials covering reciprocal crosses between half sibs (Table 3).
The difference between reciprocal crosses with respect to yield of copra is not significant.

II
When the data of 11 field trials at Kima Atas are regrouped, six families could be distinguished, each having selfed and out-crossed progenies (Table 2).Selfed is taken as crosses between half sibs, and ou^crossed as crosses between unrelated palms.The out-crossed progenies in families 1,2 and 99 have given significantly more copra than the selfed, indicating a loss in vigour due to selling.

Yield potential
The Kima Atas population of palms has given 123 nuts/32, 3 kg copra per palm/yr., equivalent to 15,130 nuts/3,970 kg copra per ha/yr.with a low density of 123 palms per ha.Further, each nut has given 260 g of copra.These figures are generally far above the data for the typica palms reported so far for a large population of palms.
The present tendency is to plant 170 palms per ha.The estimated yield of Kima Atas palms on that basis will be about 18,000 nuts ha/yr, after allowing a 15% drop in the yield of the individual palms owing to the higher density of plants.
A population of 5,700 progenies of Sri Lankan Tall x Sri Lankan Tall growing at the Seed Garden in Sri Lanka, has given an average yield (5-year period) of 18,000 nuts ha/yr, with a range of 17,500 to 25,000, under rainfed conditions.The variations are related to the rainfall pattern.The block has 165 palms per/ha.

The Indonesian and Sri Lankan examples cited above clearly demonstrate the high yield potential of improved varieties of the typica var of coconuts.
There are six palms amongst the Kima Atas population that have given more than 52 kg copra per palm/yr: (Table 4).They have produced per palm/yr: 18 bunches and 168 nuts /58 kg copra with 345 g copra per nut.The best yielder recorded 180 nuts/69 kg copra per year.

General combining ability
It is possible to assess the general combining ability of a coconut palm by crossing it to a number of unrelated palms and studying the family mean realative to the F 1 population mean.
The Kima Atas population has progenies of half sibs crossed to the other palms, which are distributed over a number of field trials.They are grouped into six families ( Yield of copra per palm/yr is not significant between the three families 32, 83 and 99 : 32 has given significantly more copra than 2, 55 and 1; 83 more than 55 and 1. Families 32 and 83 do not show an inbreeding depression (see section 5.3).Further, amongst the best six exceptionally high yielding palms at Kima Atas (Table 4), two of them have been derived by crossing half sibs of 32 and 83.Therefore, the parental palms 32 and 83 could be broadly classified as having general combining ability, broadly because half sibs are involved in the study.

Inbreeding depression
If matings between half sibs are considered to be sellings, then the inbreeding dep ression could be calculated from the Kima Atas population (Table 2) as follows: outcrossed-inbred Weight of copra of (families) x 100 outcrossed The inbreeding coefficient has varied from 0 to 15%.Inbreeding depression was shown in families 1, 2 and 99, but not in families 32, 55 and 83.It could be concluded that the high yield (copra) in the latter group is not due to heterosis effects, probably to the cumulative effect of additive genes.
The selfed and out-crossed progenies of families 32 and 83 have given 10% more copra than the population, but not 55 % considering these factors, families 32 and 83 are composed of valuable genetic material, suitable for breeding for high.yield of copra and they should be preserved.

The potential of progenies of 32 x 83
Fortunately, there are 24 progenies of the cross 32 f 11 x 83 g III in the Kima Atas population.They have given: 16 bunches per palm/yr 134 nuts " 38.95 kg copra " 291 g copra per nut The above production amounts to 16,500 nuts/4,800 kg copra per ha/yr based on the density of 123 palms per ha.It could be assumed that with a larger density of palms, say 170 palms per ha, production will reach 19,500 nuts/5,600 kg copra per ha/yr, allowing a 15% drop in yield per palm due to the higher density.
taken as open-pollinated progenies of a single palm, eg half sibs of palm no.1:1 c II, I g III, I h III, etc.
Cross A, B etc., see Appendix 1.
originated from palm No. 1 of IT selected by Tammes from the village groves and similarly for the others.

Table 1 .
. Mean yield of kima atas Trial

Table 3 .
Yield data of progenies of reciprocal crosses