• Journal of Sericultural and Entomological Science
• /
• v.40 no.2
• /
• pp.97-104
• /
• 1998

Mainly due to limited genetic resources available and also urgent need for hybrids suitable to local conditions, conventional theories and regular methods for bivoltine silkworm breeding are not easily applicable in such a tropical country as Sri Lanka which is recently planning to scale-up the silk industry. A simplified but practical methodology was introduced to overcome such constraints. Through application of such modified informal breeding methods, two hybrids named DP0308 and DP0314 were selected for cocoon production. Details of the altered method of germplasm improvement in the silkworm are presented, along with combining ability and heritability estimates for six parental pure lines in a half-diallel cross.

• Journal of Integrative Natural Science
• /
• v.5 no.2
• /
• pp.135-138
• /
• 2012

The reduction of efficiency of missing observations on complete diallel cross designs are examined. we studies robustness of optimal block designs for estimating general combining ability against loss of missing observations in diallel cross. A-efficiencies suggest that these designs are fairly robust. Simple g-inverses may be found for the information matrices of the line effects which allow evaluation of expressions for the variances of the differences between the pairs of line effects with missing observations. we numerically calculate the reduction of efficiency for estimating general combining ability against loss of missing observations in diallel cross.

• Communications for Statistical Applications and Methods
• /
• v.8 no.3
• /
• pp.677-683
• /
• 2001

In this paper, optimal block designs for complete diallel crosses are proposed. These optimal block designs for estimating general combining abilities are constructed by using balanced incomplete block designs and nested balanced incomplete block designs. Also, the efficiency of the optimal block design obtained through this method is reported in table.

• Proceedings of the Korean Statistical Society Conference
• /
• 2001.11a
• /
• pp.121-124
• /
• 2001

In this paper, partial diallel crosses designs are proposed. These designs for estimating general combining abilities are constructed by using m-associate class partially balanced incomplete block designs. Also, the efficiency of the partially diallel crosses designs obtained through this method is reported in table.

• Communications for Statistical Applications and Methods
• /
• v.9 no.2
• /
• pp.435-441
• /
• 2002

In this paper, orthogonal block designs for partial diallel crosses are proposed. These partial diallel crosses block designs for estimating general combining abilities are constructed by using $\alpha$-resolvable partially balanced incomplete block designs. Also, the efficiencies of the partial diallel crosses block designs obtained through this method are reported in table.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.2
• /
• pp.91-106
• /
• 2013

Exserohilum turcicum is considered serious destructive disease of maize (Zea mays L.) in North Korea. This study aimed to understand genetic inheritance and combining ability of newly bred lines of maize tolerant to E. turcicum by diallel crosses. Three diallel sets for two different ecological regions and one agronomic trait; eastern (E), northern (N) and stay green (SG) involving 29 inbred lines were tested in eight locations of 2000 and 2001. E. turcicum infections were under natural conditions, respectively. Lines used were selected for high yield potential in test crosses with good agronomic traits and tolerance to biotic and abiotic stresses. Selection for race specific high resistance to biotic stresses was avoided to select quantitatively inherited genes. Host plant responses to E. turcicum were rated on a scale of 1 (highly tolerant) to 9 (highly susceptible). Highly significant variations were recorded in all trials. General combining ability (GCA) mean square was roughly twice that of specific combining ability (SCA). The genotype (G) by environment (E) interaction was highly significant. The overall results of genetic studies in three diallel sets show that genetic control for inbred tolerance to E. turcicum is polygenic and quantitatively inherited. New inbreds; E-3, N-1 and SG-4 confer better tolerance to E. turcicum than the widely used inbreds; Mo17, and B73. Proper use of genetic information from this study shall increase of corn production under high E. turcicum infection in the Far Eastern Regions of Korea and China.

• Journal of Sericultural and Entomological Science
• /
• v.39 no.2
• /
• pp.205-209
• /
• 1997

In a line X tester crossing programme (24 lines 2 testers) the general combining ability (GCA) and specific combining ability (SCA) effects were analyzed for five economic characters in the bivoltine silkworm, Bombyx mori L. The results showed desired GCA effects in 934D1 (9500), 934B (9789) and 934A1 (9855) for cocoon yield per 10,000 larvae brushed by number. Likewise, the lines found to be superior based on GCA effects for other characters were as follows; 931D (14.040 Kgs), 935E (17.023 Kga.), 934D1 (15.643 Kgs.) and 934B (15.687 Kgs.) for cocoon yield by weight: 931D (1.717 g) and 930E (1.796 g) for single cocoon weight; 932B (0.330 g) for single shell weight: 931D (1.717 g) and 930e (1.796 g) for single cocoon weight; 932B (0.330 g) for single shell weight; 932B (18.7%), 933A (18.86%) and 935A (19.89%) for shell ratio. SCA effects showed the superiority of 932D$\times$KA (9822 cocoon yield per 10,000 larvae brushed by number); 932A$\times$NB4D2 (16.933 Kgs. cocoon yield per 10,000 larvae brushed by weight); 931C$\times$KA (1.911 g single cocoon weight); 934$\times$NB4D2 (0.371 g single shell weight and 21.0% shell ratio). The analysis indicated non-additive gene action for all the five characters.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.13 no.1
• /
• pp.7-14
• /
• 2006

A breeding programme was initiated during 2001 to introduce sex-limited larval markings to a productive multivoltine breed - BL67 from an inbred sex-limited line, MY1 (SL) maintained at Central Sericultural Research and Training Institute, Mysore. Introgressive hybridization, recurrent backcrossing for six generations followed by sib-mating resulted in synthesis of a new multivoltine silkworm breed BL67 (SL) with sex-limited larval markings. The new breed was studied for combining ability by crossing with eight bivoltine breeds viz., $NB_4D_2,\;CSR_2,\;CSR_2 (SL),\;CSR_2,\;CSR_4,\;CSR_8,\;CSR_{18}\;and\;CSR_{19}$. General combining ability effects of the new breed showed its superiority over the popular Pure Mysore by expressing significant GCA effects for six out of twelve characters whereas the results are on par with the original multivoltine breed. The hybrid $BL67(SL){\times}CSR2(SL)$ excelled in several quantitative characters such as pupation rate (90.2%), cocoon weight (1.97 g), cocoon shell weight (40 cg), cocoon shell ratio (20.3%), filament length (918 m), denier (2.96), raw silk percentage (14.96%) and neatness (90 p). Studies on cocoon size variability revealed that the cocoons of $BL67(SL){\times}CSR2(SL)$ were found comparatively uniform showing less standard deviation of 6.55 and co-efficient of variation of 3.91 %. The suitability of newly developed breed for easy grain age operation and commercial exploitation with promising hybrid have been discussed.

• Journal of Sericultural and Entomological Science
• /
• v.35 no.2
• /
• pp.100-104
• /
• 1993

The genetics analysis for weight of matured silkworm(WMS) and number of eggs produced per moth(NEM) was studied by the seven parents diallel. Mean squares of additive effect, dominant effect, maternal effect and reciprocal effect were significant for two characters observed. The component of genetic variance analysis for WMS and NEM showed that dominant effect was higher than additive effect. Narrow sense heritability(h2ns) estimates were 0.773 and 0.228, in the WMS and NEM. The estimate of broad sense heritability(h2bs) value was higher than that of h2ns because of the low importance of dominance effect. Incomplete dominance was shown by Vr-Wr graphic analysis in the weight of matured silkworm and overdominance in the number of eggs produced per moth. In general combining ability effect, Jam 107 and Jam 124 was showed positively high for WMS and Jam 107 and S1 was expressed positively high for NEM. In specific combining ability effect, hybrids in S1XC51, S1XJam124 and Jam 107XJam 108 were exhibited positively high for WMS and Jam 107XN63, S1XC51, N74XJam 108 and Jam 107XJam 108 were found positively high for NEM.

• Journal of the Korean Society of Tobacco Science
• /
• v.15 no.1
• /
• pp.34-48
• /
• 1993

This experiment were conducted to investigate heterosis and combining ability for several mutant characters by analyzing dialled crosses of flue-cured tobacco. In a dialled cross of 3 flue-cured varieties and the mutant line 83H -5, the heterosis was somewhat higher in Fl than in F2. For growth character, the heterosis was 0.28-6.03% in plant height, leaf number, leaf shape index and yield, and was 43.2% for bacterial wilt disease index. The mutant line 83H-5 showed significantly negative GCA effect for plant height, leaf width and bacterial wilt disease index in Fl and F2, leaf length in F2, and positive GCA effect for total alkaloids, total nitrogen in Fl and days to flower in F2, respectively. Specific combining ability(SCA) in 83H-5 x Hicks was significant in negative effect for leaf length(F2), number of leaves(F2), leaf shape(F1, F2), bacterial wilt(F2) and alkaloids(F1), and in 83H-5 x NC 2326 in positive effect for leaf length(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in positive effect for plant height(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in Positive effect for Plant height(F1, F2), leaf length(F2) and yield(F1, F2).