الفهرس 
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Abstract
This study was carried out to study performance, heterotic response, combining ability and phenotypic correlation among studied traits in yield of grain sorghum.
Thirty two grain sorghum crosses developed at Shandaweel Agric. Res. Station, Sohag, Egypt, in 2003 summer season. These crosses were developed from eight introduced cytoplasmic male sterile lines (CMS- lines) and four restorer lines (R- lines) using line x tester mating design.
Thirty two grain sorghum crosses and eight introduced cytoplasmic male sterile lines (CMS-lines), four restorer lines (R-lines) and hybrid Shandaweel-6 as the check were evaluated at Shandaweel Agric. Res. Station, Sohag and Sids Agric. Res. Station, Beni-Suef in 2004 and 2005 seasons. Data were recorded on days to 50 % blooming , plant height, number of green leaves per plant pre harvest, panicle length, panicle width, 1000 grain weight and grain yield per plant. The collected data were statistically analyzed over both locations and two seasons. Also the combining ability was estimated from the line × tester analysis and the correlation among pairs of traits were estimated. The results obtained could be summarized as follow
Mean performance:-
Analysis of variance:
A combined analysis of variance over two years and two locations showed significant differences between years for all the studied traits except plant height. Also, highly significant differences were found between the two locations for all the studied traits. Moreover, the genotypes were highly significant for all studied traits. The interaction between years with locations was significant or highly significant for all the studied traits except plant height and grain yield per plant. While, the interactions between genotypes × years and genotypes × locations were highly significant for all the studied traits, reflecting to need evaluate the genotypes under a variety of locations and years. whereas, the interaction between genotypes × years × locations were significant or highly significant for all studied traits except plant height and grain yield per plant.
Days to 50% flowering:
Most of the crosses were earlier than its parents, reflecting presence the heterosis. Most the genotypes (crosses and parents) were earlier at Sids compared to Shandaweel location, also, most the genotypes (crosses and parents) were earlier in season 2005 compared to season 2004. In addition to, some genotypes were varied in flowering from location to another and from year to year, reflecting significant of variance interactions between the genotypes × locations and the genotypes × years. Moreover, the earliest crosses were (ICSA-88007×RTX-2737) and (ICSA-91003×RTX-2737) at the two locations and combined over two locations in 2004 and 2005 seasons, respectively. In general the female parents ICSA-47, ICSA-88007, ICSA-91003 and ATX-631 gave the earliest crosses at the combined over two locations compared to the other female parents. Also, the male parent RTX-2737 gave the earliest crosses compared to the other male parents.
Plant height (cm.):-
The cross (ICSA-91003×RTX-436) was significantly taller compared to the check hybrid Sh-6 at Shandaweel, Sids and over locations in the two seasons. Most of the crosses were taller than its parents, reflecting presence of heterosis. Most the genotypes (crosses and parents) varied in plant height from location to another and from year to year, reflecting the significant of variance interaction between the genotypes × locations and the genotypes × years. Moreover, the tallest cross was (ICSA-91003×RTX-436) at the two locations and combined over two locations in the two seasons. In general the female parents ICSA-91003 followed by ICSA-88007 and ICSA-47 gave the tallest crosses compared to the other female parents. Also, the male parent RTX- 436 followed by RTX- 433 gave the tallest crosses compared to the other male parents.
Number of green leaves:-
Most of the crosses had high number of green leaves / plant compared to the parents, reflecting presence the heterosis. Most crosses had high number of green leaves / plant at Shandaweel compared to Sids location. Also, some of the genotypes were varied in number of green leaves / plant from location to another and from year to year, reflecting the significant of variance interaction between the genotypes × locations and genotypes × years. In a combined over the two locations the best crosses were (ICSA-88007×RTX-2737) and (ATX-631×RTX-433) in 2004 and 2005 seasons, respectively. In general the female parents ICSA-88007, BTX-631, SPGM (A)-94016 and ICSA-1 gave the best crosses compared to the other female parents. Also, the male parents RTX- 2737and RTX-433 gave the best crosses compared with the other male parents.
Panicle length (cm):-
Most of the crosses had longer panicle length compared to the parents, reflecting presence the heterosis. Most of the genotypes (crosses and parents) varied in panicle length from location to another and from year to year, reflecting the significant of variance interaction between the genotypes with locations and the genotypes with years. In the combined over two locations, the cross (SPGM (A)-94016×RTX-436) was the longest panicle in season 2004 and season 2005. In general the female parent (SPGM (A)-94016) gave the best crosses compared to the other female parents followed by ICSA-88007. Also, the male parent RTX- 436 gave the best crosses compared to the other male parents.
Panicle width (cm):-
Most of the crosses had higher panicle width compared to the parents, reflecting presence the heterosis. Most the crosses had higher panicle width at Shandaweel compared to at Sids location. Some genotypes (crosses and parents) were varied in panicle width from location to another and from year to year, reflecting the significant of variance interaction between the genotypes × locations and the genotypes × years. In a combined over the two locations the widest crosses in panicle were (ICSA-89002×RTX-430) and (ICSA-47×RTX-433) in season 2004 and season 2005 respectively. In general, the female parents (ICSA-89002) gave the widest crosses in panicle width compared to the other female parents followed by (ICSA- 47). Also, the male parents (RTX-430) and (RTX-433) gave widest crosses in panicle width compared to the other male parents.
1000 grain weight (gm):-
Some of the crosses had high 1000 – grain weight compared to their parents reflecting presence the heterosis. Most the genotypes (crosses and parents) had higher in 1000-grain weight at Sid compared than at Shandaweel location, also, most the genotypes (crosses and parents) had higher 1000-grain weight in season 2004 compared than season 2005 and some genotypes (crosses and parents) were varied in 1000-grain weight from location to another and from year to year, reflecting the significant of variance interaction between the genotypes × locations and the genotypes × years. In a combined over two locations the cross (ICSA-91003×RTX-430) and (ATX-631×RTX-436) were heaviest 1000 grain weight in season 2004 and season 2005 respectively. In general the female parents (ICSA-91003) gave the best crosses in 1000 grain weight compared to other female parents followed by (ATX-631). Also, the male parent RTX-430 gave the best crosses in 1000 grain weight compared to other male parents followed by RTX- 436.
Grain yield per plant (gm):-
Four out of the 32 crosses (ICSA-47 × RTX-430, ICSA-47 × RTX-433, ICSA-47 × RTX-436 and ICSA-47 × RTX-2737) produced significantly higher grain yield / plant compared to the check hybrid Sh-6 at Shandaweel, Sids and combined over locations in the two seasons. These crosses can be evaluated in a large scale and could be considered as promising crosses. Moreover, most of the crosses had high grain yield / plant compared to its parents, reflecting presence the heterosis. Most of the genotypes (crosses and parents) had high grain yield / plant at Shandaweel compared to Sids location. Also, most the genotypes (crosses and parents) had high grain yield / plant in 2005 season compared to 2004 season and some genotypes (crosses and parents) were varied in grain yield / plant from location to another and from year to year, reflecting the significant of variance interaction between genotypes × locations and genotypes × years. In general the female parents ICSA- 47 gave the highest crosses compared with the other female parents. Also, the male parent RTX- 436 gave the highest crosses compared with the other male parents.
Heterosis:-
Days to 50% flowering, most of the crosses exhibited negative and significant or highly significant heterosis (earliness) in 2004 season at Shandaweel (30 crosses), Sids (25 crosses) and over two locations (25 crosses). In addition, approximately 50 % from crosses exhibited negative and significant or highly significant heterosis in 2005 season at Shandaweel (16 crosses), Sids (15 crosses) and over two locations (12 crosses), indicated that these crosses was earlier than earliest parents.
Plant height most of the F1 crosses in 2004 season showed positive heterosis for plant height at Shandaweel (29 crosses), Sids (27 crosses) and over two locations (25 crosses). In addition, most of the crosses in 2005 season exhibited positive and highly significant heterosis at Shandaweel (27 crosses), Sids (30 crosses) and over two locations (22 crosses), indicated that these crosses were tallest than the taller parents.
Number of green leaves per plant most of the crosses showed positive and significant or highly significant heterosis in 2004 season at Shandaweel (29 crosses), Sids (17 crosses) and over two locations (19 crosses). Moreover, most of the crosses in 2005 season exhibited positive and highly significant heterosis at Shandaweel (28 crosses), Sids (18 crosses) and over two locations (15 crosses), indicated that these crosses were higher than the highest parents of No. of green leaves.
Panicle length18 and 23 crosses at Shandaweel showed positive and highly significant heterosis in 2004 and 2005 seasons, respectively. whereas, at sids 20 and 15 crosses exhibited positive and significant or highly significant heterosis in 2004 and 2005 seasons, respectively. Moreover, at the combined over two locations 18 and 13 crosses showed positive and significant or highly significant heterosis in 2004 and 2005 seasons, respectively. indicated that these crosses were longest than the longer parents of panicle length.
Panicle width 30 and 32 crosses at Shandaweel showed positive and highly significant heterosis in 2004 and 2005 seasons, respectively. whereas, at sids 31 and 25 crosses exhibited positive and significant or highly significant heterosis in 2004 and 2005 seasons, respectively. Moreover, at the combined over two locations 26 crosses showed positive and significant or highly significant heterosis in 2004 and 2005 seasons. indicated that these crosses were widest panicle than the wider parents of panicle.
1000 grain weight most of the F1 crosses had negative and significant or highly significant heterosis at Shandaweel, Sids and combined over two locations in the two seasons, indicating that these crosses had lesser 1000-grain weight than the best parent. On the other hand, only one cross had positive and highly significant heterosis.
Grain yield per plant all of the F1 crosses showed positive and highly significant heterosis for grain yield/plant at Shandaweel, Sids and combined over two locations in the two seasons, indicated that these crosses had higher grain yield/plant than the best parent.
Combining ability:-
A combined analysis of variance (Line ×Tester) over two locations showed that locations mean squares were highly significant in the two seasons for all studied traits reflecting the effects of locations on yield and other studied traits. In addition, highly significant differences were found within genotypes, crosses, parents and parents vs crosses in the two seasons for all the studied traits. Moreover, mean squares of males, females, males × females were highly significant in the two seasons for all the studied traits except, mean squares of number of green leaves for males in 2004 season and for females in 2005 season. Mean squares of interactions between locations with each of genotypes, crosses and parents were highly significant in the two seasons for all the studied traits except genotypes × locations for plant height in 2004 season, crosses × locations for days to 50% flowering in 2005 season and (parents × locations for days to 50% flowering, plant height and panicle width in 2004 season and for days to 50% flowering and number of green leaves in 2005 season). Also, mean squares of interactions between locations with males × females were highly significant in the two seasons for all the studied traits except for panicle width in 2005 season. Moreover, the interaction between locations and males was significant or highly significant for all the studied traits in 2004 season except for plant height and number of green leaves, while, in 2005 season it was insignificant for all the studied traits except for panicle length and panicle width. whereas, the interaction between locations and females was significant or highly significant for all the studied traits in 2004 and 2005 seasons except for days to 50% flowering, plant height, number of green leaves and panicle width in 2004season and for days to 50% flowering and panicle width in 2005 season.
Partitioning sum of squares of crosses to their contributions, it could be indicated that both additive and non-additive effects were involved in the inheritance of all the studied traits and the non additive effects were more important than additive effects for days to 50% flowering and 1000 grain weight. whereas, the additive effects were more important than non additive effects for plant height and grain yield per plant.
General and specific combining ability (GCA and SCA) effects, were effective in predicting crosses performance of grain yield/plant and another studied traits ( days to 50% flowering, plant height, number of green leaves per plant, panicle length, panicle width, 1000 grain weight and grain yield). Moreover, most of the early crosses, at Shandaweel and Sids locations had negative significant SCA effects. Furthermore, most of the early crosses resulted from crossing lines having negative GCA effects. whereas, the late flowering crosses had positive SCA. On the other side, most of the superior crosses of the studied traits at Shandaweel and Sids locations in the two seasons had positive significant SCA effects and resulted from crossing lines having positive GCA effects.
Phenotypic correlation:
Days to 50% flowering had negative and significant or highly significant correlation with number of green leaves per plant, panicle length, panicle width, and grain yield per plant. The correlation between days to 50% flowering and plant height was negative and insignificant. While, the correlation between days to 50% flowering and 1000 grain weight was positive and significant. Moreover, the correlation between grain yield / plant with each of plant height, number of green leaves, panicle length and panicle width was positive and highly significant, while it was negative and highly significant with days to 50 % flowering and 1000- grain weight.