Line x examiner analysis was carried out in Indian potato ( Arachis hypogaea L. ) to gauge the ground-controlled approach ( general uniting ability ) effects of parents ( 6 lines and 4 examiners ) and the SCA ( specific uniting ability ) effects of the crosses for pod output and three other quantitative traits. Analysis of discrepancy revealed extremely important differences among interventions, parents, parents vs. crosses and crosses for cod and haulm output. The estimations of discrepancy of specific uniting ability effects, ratio of discrepancy of general uniting ability to specific uniting ability and grade of laterality indicated preponderance of linear cistron effects for each trait. On over all bases, function of examiners in the look of the traits was more than lines and line – examiner interaction. However, lines contributed more than examiners and lines x tester interaction for cod and haulm output. Based on average public presentation and GCA effects for output and its assorted traits, three lines ; Samnut 2, Samnut 23 and ICIAR19BT were identified as possible parents to be used for development of high giving genotype. Loanblends like Samnut 23 X ICGV-IS 07820, Samnut 23 X ICGV-IS 07837 and Samnut 21 X ICGV-IS 07828 showed high average public presentation, SCA effects for cod and haulm output and are proposed for hybrid vigor genteelness.
Keies: Line x examiner, general and specific uniting ability, hybrid vigor genteelness
Groundnut ( Arachis hypogaea L. ) is grown by little holder husbandmans under rain fed conditions with limited inputs. Asia and Africa history for a major part of the universe ‘s Indian potato production. Production is lower than expected in both Asia and Africa due to a figure of biotic and abiotic factors that cut down output that are frequently beyond the range of resource hapless husbandmans. Groundnut is the chief beginning of human dietetic protein, oil, fat and vitamins such as vitamin B1, vitamin B2 and nicotinic acid in parts of Asia and Africa ( Savage and Keenan 1994 ) . Groundnut paste is an of import beginning of Calories for little kids, peculiarly those being weaned. These kids can non obtain the Calories they require from high majority cereal grains and depend on Indian potato for energy every bit good as vitamins. Groundnut bar and halm ( straw roots ) are used as farm animal provender and aid to keep livestock productiveness. The harvest besides contributes up to 60 kg/ha N to the dirt, profiting harvests later planted in the same field ( Sprent 1994 ) .
Engendering schemes for developing loanblends with high output potency and better grain quality require the expected degree of hybrid vigor and uniting ability. In engendering for high output harvest workss, the breeders frequently face with the job of choosing parents and crosses. Uniting ability analysis is one of the effectual attacks available for gauging the uniting ability effects that help in choosing desirable parents and crosses for the development of hybrid vigor.
The survey was under taken to find the nature and magnitude of cistron action for output and output constituents to research the best combination of male and female. The information obtained therefore will be used in choice of suited parents and pick of appropriate genteelness methods to develop high giving groundnut assortment.
Materials and Methods
Six lines of Indian potato viz. , Samnutn21, Samnutn22, Samnutn23, ICIAR 19BT, ICIAR 7B and ICIAR 6AT ( female parents ) and four examiners ICGV-IS 07820, ICGV-IS07821, ICGV-IS 07828 and ICGV-IS02158 ( male parents ) were crossed in July, 2010 at the Institute for Agricultural Research, Ahmadu Bello University, Zaria. Necessary safeguards were taken to avoid the taint of familial stuff at the clip of traversing. Emasculation of the flower buds was done and sufficient intercrossed seeds for each cross were produced through manus pollenation. 24 F1 seeds along with their parents were planted in a 9 ten 4 rectangular lattice design with three reproductions during 2011 raining season. The genotypes were assigned at random to experimental unit in each block and each row contained 20 workss. Inter-plant and inter-row spacing were maintained at 0.15 and 0.75 m, severally. Two seeds per hole were sown. The experimental population was kept under normal agronomic attention from seeding to adulthood following IAR recommendations. At adulthood, informations were recorded on agronomic traits as works tallness, yearss to adulthood, pod output ( ton -1 hour angle ) , and haulm output ( ton -1ha ) . The information for all the traits were analyzed utilizing an Synergistic SAS Macro Program for Line – Examiner analysis described by Bartolome and Gregorio, 2000 in order to analyze the uniting ability of the parental lines. The amount of squares for loanblends was further partitioned into fluctuation due to lines, examiners and lines-testers interactions. The average squares due to lines and examiners were tested against the average squares due to line- examiner, and the latter were tested against the pooled mistake. Standard mistakes for GCA effects of females ( lines ) and males ( examiners ) and the SCA effects were besides estimated. Two-tailed t-tests were used to prove the significance of the GCA and SCA effects. Estimate of GCA discrepancies ( ) and SCA discrepancies ( ) were obtained as suggested by Singh and Chaudhary ( 1985 ) . Ratios of average square constituents associated with discrepancy of GCA and SCA effects were computed as suggested by Baker ( 1978 ) to gauge the comparative importance of GCA in explicating public presentation. The closer the ratio is to integrity, the greater the predictability of offspring public presentation based on GCA effects entirely. Statistical theoretical account for the combined analysis of parents and crosses as suggested by Arunachalam ( 1985 ) as:
where, = value of the observation recorded on the ( cross in the reproduction ; is the general consequence ; is the consequence of the line ; is the consequence of the examiner ; is the specific uniting ability ( sca ) consequence of the cross ; is the block consequence and is the environmental consequence associated with the observation which is assumed to be usually and independently distributed.
Consequences and Discussion
The analysis of discrepancy affecting 10 parental lines and twenty four crosses for four characters ( Table 1 ) revealed extremely important differences among parents and the crosses. The average squares due to parents, crosses, and line x examiner interactions were important for cod and haulm output. The important constituent of discrepancy due to parents vs. crosses indicated prevalence of hybrid vigor for these characters. The average squares due to lines and examiners were besides extremely important for cod and haulm output bespeaking the importance of linear cistron effects as the chief cause of the ascertained familial fluctuation for these traits. Besides, the average squares due to line x examiner was important for these characters bespeaking that both linear and laterality or non-additive discrepancies were of import for those characters. Both linear and non-additive cistron actions appeared to play a important function in commanding the look of these traits, but nonadditive cistron action seemed to be more of import. These types of cistron action appear to be playing a considerable function in Indian potato genteelness.
The importance of the beginning of fluctuation is indicated by the comparative magnitude of discrepancy constituents. The discrepancy constituent estimations of SCA were greater than that of GCA for works tallness, pod output and haulm output ( Table 1 ) . In add-on, the ratio of the average square constituents associated with discrepancy of GCA and SCA was much less than the theoretical upper limit of integrity for all traits except adulthood clip. These consequences tend to propose that familial fluctuation among crosses was chiefly of the non-additive type. In add-on, the extremely important discrepancy due to rear versus loanblend, which is a step of mean hybrid vigor, besides points to the importance of non-additive familial consequence in finding these traits
The choice of parental lines for intercrossed plans was one of the aims of this survey. Therefore, the estimations of the general combine ability of a parent provide of import indexs of its potencies for bring forthing superior lines. A low Gb estimation, whether positive or negative, indicates that the mean of a parent in traversing with the other, does non differ greatly from the general mean of the crosses. On the other manus, a high estimation indicates that the parental mean is superior or inferior to the general mean. This gives information about the concentration of prevailing cistrons with linear effects ( Cruz and Regazzi, 1994 ) .
Estimates of GCA effects for works tallness, adulthood clip cod and haulm output for the nine parents used in this survey are presented in Table 2. The female Samnut 23 and ICIAR19BT were the best general combiner for adulthood clip, cod and haulm output with extremely important and positive GCA effects. On the other manus, the female Samnut 21 showed important and negative GCA effects for cod and haulm output. The female ICIAR6AT showed no important consequence for the trait studied.
Among the male parents, the examiners ICGV-IS07828 is the best combiner for cod and haulm output with important GCA effects. Since, high consequence is attributed to additive and linear x linear type of cistron actions, these parents could be used in engendering programme for output betterment through pureblood genteelness. The examiner ICGV-IS07821 had negative consequence for both cod and haulm output, its engendering value for intercrossed production was instead low. Sing the stuff used in this survey, parents that showed negative GCA for both grain output and seed weight likely should non be hybridized inter Se, since familial addition would non be expected for these traits in these stuffs, due to deficient linear familial discrepancies.
The estimations of provide of import information about the intercrossed public presentation as related to its parents, demoing the importance of non-additive interaction due to big or minor cistron effects in peculiar intercrossed combination. The estimations of SCA effects of selected crosses are presented in Table 3. The magnitude of SCA estimations varied among crosses. High positive SCA estimations for grain output were obtained from the undermentioned crosses Samnut 23 X ICGV-IS 07820, Samnut 21 X ICGV-IS 07828 and ICIAR7B X ICGV-IS 07821 It was observed that big positive SCA consequence for cod and haulm output was obtained by the cross Samnut 21 X ICGV-IS 07828 and at least one parent of this coupling had positive GCA consequence for this trait.
The crosses that recorded high SCA effects, coupled with high per se public presentation for output involved either one or both of the parents with good GCA for the trait being considered. The parents that were the best general combiners did non ever produce the best intercrossed combinations. This may hold been expected because of deficiency of higher order linear interactions. This trouble in foretelling the productiveness degree of the loanblend, on the footing of GCA entirely should ask testing of specific male-female combination. However, in all high giving up loanblends at least a good general combiner was involved. Harmonizing to Marilia et Al. ( 2001 ) , the SCA consequence entirely has limited value for parental pick in engendering plans. The SCA effects should be used in combination with other parametric quantities, such as intercrossed agencies and the GCA of the several parents. Therefore, intercrossed combination with high mean, with favourable SCA estimation and affecting at least one of the parents with high GCA, would be given to increase the concentration of favourable allelomorphs ; an appreciable state of affairs to any breeder.
These crosses besides showed important hybrid vigor for output and its contributing characters. It was observed that crosses affecting, one high and the lower low, medium or high general combiner parents bespeaking additive every bit good as non linear familial interactions are runing in these crosses. The best combiners for more than one trait could be utilized in farther genteelness programme. The loanblends Samnut 23 X ICGV-IS 07820 and Samnut 21 X ICGV-IS 07828 could be used for the development of hybrid vigor for output and related characters. Biparental coupling followed by choice might be worthwhile for furthering greater recombination in these crosses ( Mothilal and Ezhil, 2010 ) .