RESULTS AND DISCUSSION
4.2.4 Number of tillers planf'
Out of 40 hybrids only nine showed significant heterosis over mid parent regarding number of tillers hill'. Among the significant heterosis five combinations: 1R73328A18R 1681 It (58.46%), I3RRI3A/BRRI I 2R (29.37%), 1R73328A/BRRI I 7R (22.43%), 1R73328A/BRRI 1 2R (21.33%), and BRRI3A/BRRII2R (19.35%) were exhibited positive and desirable values. Rest four hybrids were possessed negative heterosis which is mostly undesirable for the trait concerned. In case of heterobeltiosis eight hybrids were observed significant in which only two were positive and rest 6 were negative heterosis (Table 8). The hybrid 1R73328A/3R1681R calTied high level (43.06%) of positive heterosis followed by BRRI3A/BRRI 1 2R (36.26%) "here the range was -24.67 to 43.06% (Table 8).
The only one hybrid 1R73328A X L3R1681R was played a remarkable role is case of standard heterosis also and it was 29.28% and 43.06% over check variety BRRI dhan33 and BRRI dhan39 respectively. On the other hand, hybrids:
111 3A/Bft6839-4 1-5-1 R (- 19.86%). BRRI I OA/BR736R (-25.66%), 1113A/BR827R (-22.46) and 1113A/BR827R (-25.69%) were observed high
negative heterosis over mid parent, better parent and check varieties respectively (Table 8).
The mean heterosis over mid parent, better parent and the check varieties were - 1.08%, -3.36%, -2.43% and -3.58% respectively. Lokaprakash Cl 0/. (1992) pointed out the importance of lieterosis of productive tillers on heterosis of yield.
4.2.5 Panicle length
More encouraging results were observed for this trait where 39 nianifested positive mid parent heterosis. Out of 39 significant combinations a total of 31 hybrids were found positive and heterotic values in connection with panicle length. The range of the heterosis lied between -0.21 % to 25.60%. The highest mid parent positive heterosis(25.60%) was expressed by BRRI 1OAJBR6723-l-I- 2R where as lowest, insignificant and negative heterosis found in BRRI I OA/BRRI I 2R.
Twenty hybrids out of 34 had significant positive heterosis over better parents.
On the other hand, none of the hybrids possessed significant heterosis. The highest positive heterosis over better parents observed in the hybrid, 1132A/BR736R (20.44%) followed by BRRI IOAIBR736R (20.16%) and
BRRI9A/BR736R (16.04%) (Table 8).
l'hirty-six hybrids exhibited positive standard heterosis of which twenty-four were significant and desirable direction and none of the hybrid was Found negative value over BRRI dhan33. On the other hand, only seven out of fifteen combinations observed significant and positive heterosis. Where as. among 25 negative heterotic crosses, 12 hybrids were possessed significant but negative values over BRRI dhan39 for this trait (Table 8). The range of the standard heterosis for panicle length was -1.64% to 18.62% and -0.12% to 9.14% in case of BRRI dhan33 and BRRI dhan39 respectively. The highest positive heterosis
'lj
was manifested by the hybrid, BRRI3A!13R827R (18.62%), followed by BRRI9A/BRI68A (18.11%), BRRI3A/BRI68R (16.48%) and BRRI9AJBRS27R (-16.23).
The mean heterosis over mid parent, better iarents and standard check were 10.01%, 5.68% and 7.47%, respectively. Lokaprakash et al. (1992) reported that the heterosis of panicle length contributed to the heterosis of yield. Mishra and Pandey (1998) also mentioned that heterosis for seed yield plantd was positive and significant for panicle length and 1000-grain weight.
4.2.6 Number of panicle meter 2
Out of 25 positive mid parent heterosis only five hybrids manifested significant value where as two hybrids were observed significantly negative heterosis out of 15 combinations (Table 8). The highest (29.72%) positive heterosis was found in BRRJ9A/BR827R. Conversely, the highest (-38.57) negative mid parent heterosis was observed in BRRI IOA/BR827R. In case of heterobeltiosis out of 12 only the one hybrid I3RRI9A/BR827R (20.26%) exhibited significantly positive heterosis.
Similarly, eight out of 2$ hybrids possessed significantly negative heterosis which ranged from -42.25% to 20.26 % over better parent (Table 8).
Similar trends of significant values were also observed for standard heterosis.
Only two hybrids out of eight were found heterotic with significant positive heterosis where 15 hybrids out of 32 were observed signiiieantly negative over BRRI dhan33 (Table 8). On the other hand, only two hybrids 1R73328A113RR110R (17.75%) and BRRI3A/BR6723-1-1-2R (14.14%) were found significant heterosis over BRRI dhan33. Contrary, 32 hybrids out of 3$
exhibited significant negative standard heterosis over BRRI dhan39 (Table 8).
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mean heterosis over mid parent, and better patent were 2.05%, and - 6.44%as well as -10.61% and -21.39% over check varieties, respectively.
4.2.7 Primary branch panicl&'
A total of 34 hybrids were found under positive heterosis and rest that of negative values in terms of mid-parent heterosis. Seventeen hybrids showed significant positive and none of them was observed significant negative. The range ofheterotic values was -2.14% to 30.23% and 1.69% at average (Table 8).
The highest positive heterosis was observed in 1R73328A/3R735R (30.23%) lollowed by 1132A/BR736R (24.09%), BRRI I OA/13R736R (22.77%), and BRRI9AJBR736R (21 .09%). Regarding heterobeltiosis, out of 23 positive combinations only the five hybrids were found significant and positive. The highest heterotic hybrid was 1R73328A/8R736R (18.79%) followed by 1132A/131627[{ (15.57%) and 1R73328A/BRI68R (13.61%). The mean heterosis was found -3.21% and the ranged was from -19.32 to 18.79% (Table 8).
Standard heterosis was observed positive for 30 and 32 combinations in which fourteen and sixteen hybrids showed significant positive heterosis over I3RRI dhan33 and BRRI dhan39 respectively. Heterosis ranged &orn -12.10 to 24.84%
and the mean was -5.2 1% over the check BRRI dhan33 and similarly, the range was -10.39 to 27.27% with mean value -6.08% over BRRI dhan39. The highest heterosis was observed in 1R73328A!BR736R (24.84% and 27.27%) over both checks (Table 8).
4.2.8 Secondary branch panicl&1
Thirty-six out of 40 hybrids were expressed positive heterosis and rest that of negative over mid-parent. Only 14 hybrids showed significant positive and none of the hybrids was observed significant negative. The range of heterotic combinations was -19.89% to 48.69 % over mid parent (Table 8). The highest positive heterosis was observed in BRRI I OAIBR736R (48.69%) followed by I3RRI9A/13R736R (42.49%). 1132A/8R736R (38.03%) 1R73328N13R736R (32.77%) and BRRI9A/BRRJI2R (32.69%). On the other hand, regarding better parent heterosis out of 26 positive combinations only 9 hybrids were found
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significant. The range of heterotic combinations was -27.57% to 47.60% .The highest heterotic hybrid was BRRT I OA/13R736R (47.60%) followed by J3RRI9A/BR736R (42.19%
In case of standard heterosis positive values were observed in 32 combinations of which only II over BRRI dhan)3 and 10 hybrids showed significant heterosis over BRRI dhan39, respectively. l-Ieterosis ranged from -15.63 to 51.39% over the check I3RRI dhan33 and from -19.10 to 45.17% over BRRI dhan39. The highest heterosis was observed in same hybrid 1R73328A/BR736R (24.84% and 27.27%) over both checks (Table 8).
The mean heterosis over mid parent, better parents and standard checks were 8.87%, 0.99% 7.37% and 9.46% respectively. None of the hybrids exhibited significant and negative heterosis over mid parent and checks except one over bettcr parent.
4.2.9 Panicle weight (gm)
Twenty-one hybrids out of 40 combinations were exhibited significant and positive heterosis over mid parent. The only one hybrid, ffl73328A1BR6839-4 I - 1-SR showed insignificant and negative value (Table 8). The highest and highly significant positive mid parent heterosis was found in BRRI9AIBRRI I OR (65.05%) followed by BRRI9A/BRRJI2R (54.89), II32AIBRRII7R (53.48%), BRRI I OA/13R827R (52.77%) and 1132A/13R736 (5 1.24%). The range of heterotic positive values was 1.70% to 65.05% (Table 8).
Out of' 37 positive combinations only 12 were showed significant heterosis (Table 8). The range of heterosis was -22.21 to 48.46% where the highest heterotic value was presented by BRRI9A/BRRI bR.
Satisfactory standard heterosis was found over BRRI dhan33 where out of 40 combinations 38 hybrids were manifested positive values. Sixteen crosses were observed with significant heterosis over the check (Table 8). The highest (56.73%) heterosis was exhibited by IR73328AJBRRII7R followed by BRRJ9A/BRR1 OR (55.19%). 13RRI9AJBRRI 1 2R (54.21%) and 1132A/BR.RI 1 7R (50.03%). Only two hybrids were found negative but insignificant regarding this trait. On the other hand, out of 25 six hybrids presented significant and positive standard heterosis where the rest 15 combinations having insignificant and negative values over I3RRI dhan39 (Table 8). The hybrid 1R73328A/RRRJ I 7R having the highest (33.03%) significant and positive heterosis followed by BRRI9A/BRRIIOR (31.71%) and BRRI9A/BRRII2R (30.88%) over BRRI dhan39.
The mean heterosis over mid parent, better parents and standard checks were 14.49%, 4.72%, 12.80% and 8.17%, respectively.
None of the hybrids exhibited significant negative heterosis over mid parent and checks except one over better parent.
4.2.10 Number of spikelet panicle4
Twenty hybrids out of 40 combinations were found significant and positive heterosis and out of seven hybrids only one exhibited significantly negative mid parent heterosis for the trait spikelet panicle" (Table 8). Mid parent heterosis was ranged from -27,76% to 70.42%. The highest positive heterosis was manifested by 1132A/BR827R (70.42%).
In case of better parent heterosis, 14 out of 24 combinations were showed significant positive values where as thur out of 16 possessed significant negative heterosis. The hybrid I132AI13R827R expressed the highest (63.62%) value among the positive combinations. Contrary, the highest negative heterosis was exhibited by BRR.I9AIBRRI I 2R (-38.78%) (Table 8).
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The result showed that 13 hybrids out of 29 possessed significant positive heterosis and only one out of II carried significant negative values over 81(1(1 dhan33 (Table 8). Similarly, out of 38 combination 28 were found significant positive heterosis where as only two hybrids were observed negative but insignificant. The same hybrid 1132A/BR827R manifested the highest (45.58%
and 71.62%) standard heterosis over BRRI dhan33 and BRRI dhan39, respectively (Table 8).
The mean heterosis over mid parent, better parent and standard checks were 18.29%, 11.23%, and 13.39%, 33.68%.
4.2.11 Spikelet fertility (%)
Out of 23 positive combinations only seven hybrids were exhibited significant lieterosis. Similarly, out of 17 negative heterotic combinations seven hybrids were exhibited significant values in terms of mid parent heterosis (Table 8). The range of mid parent heterosis varied from -22.37% to 25.71%. The highest heterotic value was observed in BRRI9AJBRRI I 2R (25.71%) followed by BRRI9A/BRRII7R (23.68%) and 1132A/BRRII2R (19.52). On the other hand, highest negative heterosis exhibited by BRRJ3A/BR6723-l-12R (-22.37%).
In case of better parent heterosis only four out of 14 hybrids showed significant and positive value while out of 26 combinations, nine hybrids were possessed significant negative heterosis. Better parent heterosis ranged from -27.69% to 19.49% where the highest and Lowest heterosis was manifested by the combinations BRRI3AJBR6723- 1-1 -2R and 11 32A/BRR.1 I 2R respectively.
Very much poor standard heterosis was observed in this trait over the both checks. Out of 15 heterotic combinations only two hybrids were found significant over BRRI dhan33. On the other hand, none of the hybrid was Ibund significant and positive heterosis over BRRI dhan39 (Table 8).
The mean heterosis over mid parent, better parent and standard checks were 1.69%, -3.21%, and -5.21%. -6.07%
4.2.12 Filled grain panicl&'
Only ten out o136 hybrids expressed significant positive mid-parent heterosis but one hybrid out of' four possessed significant negative values (Table 8). The highest positive mid parent heterosis (67.40%) was given by lI32A/BR827R where it ranged froni -0.98 to 67.40%.
The extent ol' better parent heterosis for this trait ranged from -22.1 8%t o 55.69%
where the highest and lowest heterosis manifested by 1R73328A/BR 1 68R and 1132A/BR827R. respectively. Seven hybrids showed significant positive heterosis
while only one hybrid exhibited significant negative heterosis (Table 8).
In contrast, 28 hybrids showed positive standard heterosis in which jive were significant and 14 hybrids showed negative heterosis over BRRI dhan33.
Similarly. 16 hybrids out of 39 possessed significant and positive heterosis and only one was negative over BRRI dhan39 (Table 8). The highest positive heterosis was exhibited by the same hybrids BRRI I OA/BR736R (49.05% and 69.15%) over BRRI dhan33 and BRRI dhan39. respectively.
The mean heterosis over mid parent and better parents as well as over standard check varieties were I 7.81%, 7.05%, 6.08% and 22.65%, respectively.
Yolanda and Das (1996) observed considerable heterosis in the six quantitative traits especially in grains panicl&'. Mishra and Pandey (1998) also reported that most of the higher yielding hybrids manifested positive heterosis for number of spikelet panicl&'.
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4.2.13 1000-grain weight
Out of 40 hybrids 22 manifested significant mid parent heterosis (Table 8).
Twenty hybrids exhibited significantly positive where as only two that of negative. The range of the mid parent heterosis was -13.19 to 13.93%. The highest value was observed in BRRI9AJBRRI 1 7R.
Among the 18 combinations only BRRI9AIBRRJ 10R (10.25%) possessed significant positive heterosis over better parent where the range was 0.21 to 10.25%. The rest 22 hybrids provided negative heterosis in which 11 were significant (Table 8). The range of negative heterosis varied from -0.42 to - 23.43%. The highly significant negative heterosis was found in 1R73328A/BRRI 12R (-23 .43%).
Eighteen hybrids out of 32 having significant and positive standard heterosis for this trait. And only two hybrids out of eight crosses were possessed significant and negative heterosis over standard check variety BRRI dhan33 (Table 8). The highest standard heterosis over BRRI dhan33 observed in BRRI9AIBRRI I 7R (44.47%). On the other hand, in ease of standard heterosis over BRRI dhan39, out of 36 positive combinations, twenty-six hybrids showed significant values.
Only four combinations observed negative but none of them were significant (Table 8).
the mean heterosis over mid parent and better parents were 1.14% and -0.44%
respectively while mean standard heterosis were 0.61 and 1.05%
4.2.14 Grain yield plant4
Considering all types oh heterosis estimated excellent heterotic combinations were observed for grain yield. All the combinations exhibited positive heterosis except 13RR13AIBR6839-4 I-S-I R and 1R73328A/BR6839-4 1-5-1 R. Twenty-nine hybrids out of 38 were found significant and positive heterosis over mid parent that was ranged from 17.68% to 68.56%. The highest mid parent heterosis was
found in I31M9A!BRRI 1 OR (68.56%). On the other hand, only one hybrid out of the rest two showed significant and negative heterosis (Table 8).
Out of 36 positive combinations 21 crosses manifested significant heterosis where as three out of four crosses exhibited significant and negative heterosis over better parent (Table 8). The range of positive varied from -33.89% to 69.17% where the highest value was observed in the hybrid BRRI9A!J3RIU I OR.
Similar trend of positive heterosis was also observed for standard heterosis.
Twenty-four hybrids out of 39 expressed significant and positive heterosis where the highest value was 64.80% in BRRI9A/BRRI1OR. Only the hybrid 1R73328A/1310839-4 1-5-1 R (-2.32%) exhibited negative heterosis over BRRI dhan33 (Table 8). On the other hand, 20 hybrids out of 37 positive combinations were showed significant values. The highest positive heterosis was found in BRRJ9A/13IUU IOR (59.3 1%). Only three hybrids manifested negative standard heterosis over BRRI dhan39 and none of them was significant (Table 8).
It is importantly noticeable that the out standing hybrid BRRI9A/BRRI I OR was the highest in all types of heterosis calculated.
Vishwakarma ci at, (1999) reported as high as 108.8% and 73.33% better parent heterosis and standard heterosis in rice hybrids.
The mean heterosis over mid parent, better parent and over standard varieties were 29.31%, 21.38% and 21.89, 22.66%, respectively.
Patnaik et at, (1990) reported 18 out of 136 hybrids gave more than 20% grain yield than the standard check.
Mishra and Pandey (1998) reported that about 1 7-20% of the hybrids derived from at least one CMS parent, 1R62829A, manifested significant and positive heterobeltiosis and standard heterosis for seed yield in the range of 44.7 to 230.9
% and 42.4 to 81 .4%, respectively.
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