Estimation of Genetic Parameter for Quantitative Characters of Pepper ( L . ) Capsicum annuum

The research was conducted at Leuwikopo Experimental Field and Plant Breeding Laboratory of IPB, Dramaga, Bogor, West Java, Indonesia from October 2012 to April 2013. Crossing population between C15 and C2 genotype were used to study genetic parameters for quantitative characters in pepper. All the characters were not controlled by maternal effect, except fruit length. Broad-sense heritability were high for plant height, stem diameter, dichotomous height, day to ower , day to ing harvest ; and medium for fruit length and diameter. ing Narrow-sense heritability was high for stem diameter, dichotomous height, day owering; medium for plant to height, day to harvest ; and low for fruit length and ing diameter. The ratio of additive variance was high for all the characters, except for fruit length and fruit diameter. Keyword : s heritability, heterosis, heterobeltiosis, additive variance, dominant variance


Introduction
Estimation of genetic parameters for quantitative characters is important for plant breeding programs.Analysis of genetic parameters is used to obtain information on gene actions, genetic variability, heritability, and other genetic information.The genetic information is of great importance to allow more ef cient and effective plant selection (Syukur et al., 2012).
There are potentials to increase pepper production in the tropics through breeding.Pepper has wide range of genetic resources which are crucial for plant breeding program (Syukur et al., 2012).Pepper breeding has been conducted through hybridisation, followed by selection (Hilmayanti et al. 2006).The selection process has high , probability to bring genetic improvements if the selected characters have high heritability.
Previous studies have reported that broad and narrowsense heritability for quantitative characters range from low to high (Ben-Cham and Paran, 2000).Broad-sense heritability, which captures the proportion of phenotypic variation due to genetic values, was high for dichotomous (Arif et al., 2012); day to ower (Lestari et al., 2006), day to harvest (Arif et al., 2012), fruit length and diameter ing (Syukur et al., 2010a).Narrow-sense heritability was low for day to harvest , medium for dichotomous (Arif et al., ing 2012); and high for fruit length and diameter.The objective of the study was to estimate genetic parameters for quantitative characters in pepper.Pepper seeds were sown on trays with pasteurised media and grown up to 6 weeks after sowing.The growing area was covered with black and silver plastic mulch prior to planting.Seedlings were then transplanted to the eld with planting distance of 50 cm x 50 cm.Organic fertiliser at 1 kg per plant, Urea at 200 kg ha , SP-36 at 150 kg ha -1 -1 -1

Materials and methods
and KCl at 150 ha were applied one week before planting.Pest and diseases were controlled by alternate weekly application of insecticide and fungicide application, or as required, at the recommended doses.Plants were fertilized weekly using 10 g.L NPK Mutiara -1 16N-16P-16K at 250 mL per plant.
Scoring was conducted on the following quantitative characters: day to owering (DAS), day to harvesting (DAS), plant height (cm), dichotomous height (cm), fruit length (cm) and fruit diameter (mm).
Broad-sense heritability was estimated using a method developed by Allard (1960 V F2 ) x 100%; where h = broad-sense heritability, V = P1 where is average of and is mean average of the best parents.

Results
Normality test was conducted to study the frequency of F2.All F2 variables had a normal frequency distribution.Continuous and normal distribution showed that the characters were controlled by polygenic genes.
F2 population had the highest variability, followed by BCP1 and BCP2 populations.P1, P2, F1 and F1R populations were more uniform than BCP1, BCP2, and F2 (Table 1).The highest variability in F2 population was due to the maximum segregation in the population.P1 a n d P 2 p o p u l a t i o n s w e r e h o m o z y g o u s a n d homogeneous, which means that each individual had the same genetic composition.F1 and F1R were heterozygous and each individual had the same genetic composition (homogeneous).
The maternal effect test showed that there was no signi cant difference between F1 and F1R for all variables (Table 2).This suggests that female parent did not affect the inheritance of the character, which indicates that these characters are controlled by genes in the nucleus.
Broad-sense heritability of all characters ranged from 43.01% to 79.5%, or classi ed as moderate to high.Broad-sense heritability estimates were high for plant height, stem diameter, dichotomous height, day to owering and day to harvesting, whereas it was were moderate for fruit length and fruit diameter.This was a re ection of the role of genetic variance.Genetic variances were greater than the environmental variance  3).
Narrow-sense heritability for all character ranged from 3.28% to 70.46%, or classi ed as low to high.Narrowsense heritability estimates were high for stem diameter, dichotomous height, and day to owering; moderate for plant height and day to harvesting, and low for fruit length and fruit diameter.This was a re ection of the role of additive variance, which was re ected in the ratio of additive variance.The ratio of additive variance was high for all the characters, except for fruit length and fruit diameter (Table 3).
Heterosis values were positive for plant height, day to owering, day to harvesting, fruit length and fruit diameter, while was negative for fruit length.However, heterobeltiosis was positive in day to owering and day to harvesting (Table 4) Heterosis and heterobeltiosis for day to ower and day to harvesting were expected to be negative as the selection for this character was directed to obtain earliness character.

Discussion
If a character is in uenced by the female parent, the offspring of the reciprocal will likely be different (from the female parent), and the offspring will show traits of its female parent.F1 and F1 reciprocal (F1R) population cannot be merged because segregation of the F2 population will be different and does not follow Mendelian segregation law.However, if there was no signi cant difference between F1 and F1R then the two populations can be merged for the purposes of this analysis.A study by Arif .( 2012) showed that dichotomous height and et al day to harvesting were not affected by maternal characters.In addition, Arif et al. ( 2011) reported there was no maternal effect for ower position, young fruit color, young stems color and texture of the pepper fruit surface.Therefore the offspring and reciprocal can be merged to obtain the next offspring, and the F2 segregation will follow Mendel's laws.
Heritability estimate of a character is important to predict whether the character is heavily in uenced by genetic or environmental factors.High heritability suggests that genetic factors had greater in uence over environment on phenotypic appearance.High heritability value, particularly the narrow-sense heritability, plays an important role in increasing the effectiveness of selection (Syukur et al., 2012).
Heritability value is between 0 and 1. Heritability value of close to 0 means the variance of phenotypes is primarily caused by environmental factors; values close to 1 means that it was mainly caused by genotype.Values closer to 1 indicate higher heritability whereas values closer to 0 indicates lower heritability (Syukur et al., 2012).
The appearance of heterosis effects was caused by the accumulation of dominant genes whereas heterobeltiosis was due to the over-dominant gene on the character.Genetic distance among two parents is one of the factors that lead to high heterosis value (Syukur et al., 2012).Daryanto et al. (2010) andSitaresmi et al. (2010) reported correlation between the parental genetic distance and heterosis.Parental genetic distance that is far apart produces high heterosis values.
The role of dominant effect on the observed character can also be seen from the ratio of additive variance.Fruit length and fruit diameter have a low ratio of additive variance.This ratio indicates that dominant variance was more in uential in controlling the character.It can also be seen from the high heterosis values in both fruit length and fruit diameter.

Conclusion
All the characters except for fruit length were not controlled by maternal effect.Broad-sense heritability was high for plant height, stem diameter, dichotomous height, day to owering, and day to harvesting, and was moderate for fruit length and fruit diameter.Narrow-sense heritability was high for stem diameter, dichotomous height, and day to owering; moderate for plant height and day to harvesting; and low for fruit length and fruit diameter.The ratio of additive variance was high for all the characters, except for fruit length and fruit diameter.