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May 2009 issue
Articles
May 2009 [ 3(3) 2009]
Table of Contents
DNA fingerprinting of rice (Oryza sativa L.) cultivars using microsatellite markers
Muhammad Shefatur Rahman, Md. Rezwan Molla, Md. Samsul Alam and Lutfur Rahman
Abstract
Microsatellite combines several features of an ultimate molecular marker and they are used increasingly in various plant genetic studies and applications. In this work, we report on the utilization of a small set of three previously developed rice microsatellite markers for the identification and discrimination of 17 HYVs and 17 local rice cultivars including two wild rice cultivars. All analyzed microsatellite markers were found to be polymorphic with an average number of 6.33 alleles per locus. These three markers were able to identify 15 local rice cultivars and 11 HYVs. A total of three variety specific alleles, RM-11/147, RM-151/289 and RM-153/178 were identified for BR-11, Badshabhog and BR-19 cultivars respectively. DNA fingerprints of rice cultivars by means of microsatellites provided meaningful data, which can be extended by additional microsatellite markers. The data obtained can be used for the protection of plant genetic resources.
Keywords: Rice; microsatellite; markers; variety identification
Pages 122-128 PDF full Text
Effect of integrated weed management on weed control and yield components of maize and cassava intercrop in a southern Guinea savanna ecology of Nigeria
Olorunmaiye Patience Mojibade and Olorunmaiye Kehinde Stephen
Abstract
The use of pre-emergence herbicides, hoe weeding and live mulch of herbaceous cover plants in a maize/cassava intercrop was investigated at the Teaching and Research Farm of the University of Ilorin, in 2002 and 2004. Experiment consisted of eight main treatments and six sub treatments. The main treatments which is the focus of this article were made up of the application of two pre-emergence herbicides [Primextra and Galex, each at 2.5 kg a.i./ha alone or with one or two supplementary hoe weedings at 6 weeks after planting (WAP) or 6 and 12WAP], a hoe-weeded check (hoeing at 3, 6 and 12WAP) and a weedy control. The experiment was laid out in a randomized complete block design with a criss-cross arrangement, and replicated three times. Data were collected for weed infestation and control, as well as for yield of food crops. When used alone, the pre-emergence herbicides gave satisfactory weed control up to 6WAP, but failed to give season-long weed control. However, better weed control was achieved when the pre-emergence herbicides were supplemented with two hoe-weedings, (P<0.05). Consequently, Primextra plus two hoe weedings (Prim+2HW) gave significantly lower weed biomass (42.9 g/m²) and higher yields of the food crops (1135 kg/ha for maize and 10,027 kg/ha for cassava) compared with the hoe-weeded control treatment (63.0 g/m², weed biomass; 849 kg/ha, maize and 8076 kg/ha, cassava), plots treated with Primextra alone (80.4 g/m², weed biomass; 678 kg/ha, maize; 1801 kg/ha, cassava) and the weedy control (116.3 g/m², weed biomass; 358 kg/ha, maize and 1425 kg/ha, cassava).
Keywords: weed; herbicides; savanna; yield; maize; cassava
Pages 129-136 PDF full Text
Effect of seed irradiation on the content of antioxidants in leaves of Kidney bean, Cabbage and Beet cultivars
N. Kacharava, Sh. Chanishvili, G. Badridze, E. Chkhubianishvili, N. Janukashvili
Abstract
Seeds of two varieties of kidney bean (Phaseolus vulgaris L., var. oratus and var. ellipticus), cabbage (Brassica oleracea L., var. capitata alba and var. capitata rubra) and beet (B. vulgaris L., saccharifera Alef. and ssp. esculenta (Salisb) Gurke, var. rubra) were exposed to ultraviolet (UV) irradiation (460-760 µW/cm2 for 30, 60 and 90 min). The purpose of the study was to evaluate the importance of pre-sowing treatment with UV for activation the antioxidative system and building up adaptive mechanisms against unfavorable environmental conditions in crops. In particular, we studied the effects of exposing seeds to UV irradiation prior to sowing on antioxidant contents in leaves of experimental plants developed from the irradiated seeds and on their physiological state and growth indices (height, biomass, photosynthetic activity of leaves, amount of plastid pigments and total proteins). Treatment of seeds with low doses of UV caused increase in ascorbic acid content in leaves of kidney bean varieties (32-35%). Applied doses of UV significantly enhanced the amount of tocopherol in leaves of both varieties of kidney bean (2-4 times and more), and white beet (5-9 times). Seed UV irradiation with high doses (90min) had clear effect on the content of plastid pigments in kidney bean varieties (about 35%), while in cabbage and beet stimulative were both doses (30min and 90min) (45% and more). UV treatment of seeds also stimulated synthesis of anthocyanins in leaves of kidney bean varieties (3-6%) and white beet (14-21%). In the case of cabbage and red beet low doses of irradiation were effective (9-20%). We conclude that UV irradiation of seeds stimulated stress adaptive mechanisms in tested plants. These effects, however, depend on the intensity of irradiation, also on plant species and varieties. Treatment of seeds with optimal doses of UV irradiation may used for stimulation of antioxidant synthesis in plants and enhance their nutritional value and tolerance to environmental stress factors.
Key words: anthocyanins; ascorbic acid; tocopherol; seeds; vegetables; ultraviolet irradiation
Pages 137-145 PDF full Text
Heterosis in yellow maize
AE Sharief, SE El-Kalla, HE Gado and HAE Abo-Yousef
Abstract
Ten new yellow maize inbred lines were top crossed to three testers i.e. Gm. 1021, S.C. 52 and Comp 21 at Gemmeiza in 2005 season. Thirty top crosses plus three checks were evaluated at Gemmeiza and Sids Agricultural Research Section, Egypt in 2006 season. Significant differences were noticed between the two locations for all the studied traits except resistance to late wilt disease. Mean squares due to crosses and their partitioning lines and testers were highly significant except 50% silking at Gemmeiza ,while lines x testers interaction were significant for plant height , ear height, resistant to late wilt disease and grain yield under two location and their combined ,while, it was significant for Gemmeiza of days to 50 % silking. At least nineteen crosses surpassed from the three checks (S.C.155, TWC. 352 and Gm.Y.Pop.) in yield potentiality. The highest mean performance were detected in the cross Gm. 3 x Gm. 1021 (15.090t/ha) followed by the cross Gm.1 x Gm. 1021 (14.640t/ha) and the cross Gm. 8 x Gm. 1021(13.731t/ha), respectively. These crosses are favorable and could be used in maize breeding programs.
Pages 146-154 PDF full Text
Genetic dissection of biomass production, harvest index and panicle characteristics in indica-indica crosses of Iranian rice (Oryza sativa L.) cultivars
Hossein Sabouri, Atefeh Sabouri, Ahmad Reza Dadras
Abstract
Improvement of rice (Oryza sativa L.) yield through breeding requires a good understanding of genetic factors that control component traits. In the current study, traits associated with this multiplicative relationship were investigated in a field trial with F2 and F2:3 population of rice. One-hundred-and-ninety-two individuals and families derived from a cross between two genetically divergent high-yielding varieties, Khazar (KHZ, indica type with a large biomass) and Tarommahalli (TAM, indica type with a low biomass), were grown in Rice Research Institute of Iran and Gonbad High Education Center to detect QTLs for biomass and related traits. Result of mapping on F2 population showed that QTLs controlling GWP (qGWP-3a and qGWP-3b) overlapped with the QTLs for number of SNP (qSNP-3a and qSNP-3b) and the QTL for HI (qHI-3). Five QTLs were mapped for harvest index. These QTLs were showed the large effects on the harvest index and explained 21.35 to 31.28% of the total phenotypic variance. Result of F2:3 population showed that QTLs controlling GWP (qGWP-2, qGWP-7 and qGWP-12) overlapped with the QTLs for number of SNP (qSNP-2, qSNP-7 and qSNP-12). Clustering of the QTLs for different traits at the same markers interval in both of mapping population was observed for GWP, HI and SNP. These result implied that HI, might partly share a common genetic basis with GWP and SNP. Our result indicated that breeding methods of QTLs pyramiding by using marker-assisted selection could be very useful for the development of new varieties with a high level of grain yield.
Keywords: biomass; grain yield; rice (Oryza sativa L.); QTL mapping.
Pages 155-166 PDF full Text
Combined effect of host plant resistance and insecticide application on the development of cowpea viral diseases
Z. Ambang, B. Ndongo, D. Amayana, B. Djilé, J. P. Ngoh, G.M. Chewachong
Abstract
Cowpea [Vigna unguiculata (L) Wap] is an important food crop which is widely grown in the Soudano-sahelian region of Cameroon. An integrated disease control approach involving insecticide treatment and plant host resistance was used to control virus-induced diseases, which are the most cowpea yield-limiting factor in this part of the country. A field experiment was conducted at Guirin-Maroua location in which three cowpea varieties (CRSP, LORI and VYA) that differ in their resistance to cowpea viral diseases were treated with Cyperdim 220 EC insecticide at different doses (1.75, 1.25 and 0.95 l/ha). In this experiment, severity of cowpea viral diseases including SMVD, YMVD, ABMVD and GMVD, were assessed. Population size of thrips (Megalurothrips sjostedti) and larvae of Maruca testuladis, two main vectors of cowpea viral diseases were evaluated. An evaluation of cowpea grain yield was also made. Visual diagnosis which was confirmed by ELISA test showed that only SMVD, YMVD, ABMVD were present during these investigations. Both viral diseases and the population of vectors reduced with combined treatment consisting of the less susceptible cowpea variety VYA and the highest insecticide dose (1.75 l/ha). This treatment combination also produced the highest cowpea grain yield (29.5 t/ha), a yield that was almost 3 times higher than the control (10.2 t/ha). Our results suggest that cowpea viral diseases that prevail in the Soudano-sahelian region of Cameroon are likely to be under control if less susceptible cowpea varieties such as VYA are treated with some insecticides including Cyperdim 220 EC.
Keywords: Cyperdim 220 EC; integrated management; natural defence; Vigna unguiculata; viruses
Pages 167-172 PDF full Text
In vitro effects of some pesticides on pathogenic fungi associated with legumes
Dare Michael Olajire and Fawole Oluyemisi B
Abstract
An in vitro effect of three pesticides commomly used in the southern Guinea savanna namely Benomyl (fungicide), Galex® (herbicide) and Karate® (insecticide) on the growth of three pathogenic fungi of legumes, Fusarium oxysporum, Aspergillus flavus and Fusarium monilliforme, was investigated to determine the effectiveness of the pesticides in reducing the growth of these fungi . Each fungicide was assayed with each fungus at 0, 100, 200, 400 and 500 mg L-1 rate in Potato Dextrose Broth (PDB) and incubated at 30°C for five days. Each treatment was replicated four times. Data were collected on the mycelia weights of the fungi under each treatment. Mycelia weights of the three fungi were significantly reduced at 100 mg L-1 by all the pesticides except that of A. flavus under Benomyl treatment where some resistance was observed. Significant reduction of mycelia weights of the three fungi was observed at 500 mg L-1 of Galex® application compared to other application rate of Galex. Application of Benomyl and Karate® significantly reduced mycelia weight of F. oxysporum irrespective of the rate applied. Growth of the two Fusarium species was completely inhibited by Benomyl at the application rate of 500 mg L-1. Galex® and Karate® which are herbicide and insecticide respectively, had detrimental effect on the tested pathogenic fungi of legumes and therefore may reduce incidence of diseases caused by these fungi in legume production in the southern Guinea savanna of Nigeria. We suggest that application of Karate or Galex can be effectively used to control some important pathogenic fungi of legumes.
Keywords: Aspergillus flavus; fungicide Fusarium monilliforme; Fusarium oxysporum; herbicide; insecticide; mycelial weight
Pages 173-177 PDF full Text
Physiological evaluation of some hybrid rice varieties under different sowing dates
Ali abdalla basyouni Abou khalifa
Abstract
A field experiment was conducted at the experimental farm of Rice research and training centre (RRTC), Sakha, kafr- El sheikh governorate, Egypt in 2008 rice season for physiological evaluation of some hybrid rice varieties under different sowing dates. Four hybrid rice H1, H2, GZ 6522 and GZ 6903 were evaluated at six different sowing dates, April 10th, April 20th, May 1st, May 10th, May 20th and June 1st. A split plot design with four replications was used as six sowing dates were allocated in the main plots, and four rice varieties in sub plots. Results indicated that early date of sowing (April 20th) is the best time of sowing for important properties such as maximum tillering (MT), panicle initiation (PI), heading date (HD), number of tillers per M2, plant height and root length at PI and HD stage, chlorophyll content, number of days to PI and HD, leaf area index, sink capacity, spikelets/ leaf area ratio, Number of grains per panicle, Panicle length (cm), 1000 grain weight (g), number of panicles per M2, five Panicle weight (g) and grain yield (T/ha). Sterility percent was the lowest value in April 20th sowing date. Sowing in 1st June has given the lowest value for all studied traits. H1 hybrid rice variety surpassed other varieties for studied characters except for number of days to panicle initiation and heading date.
Keywords: Normal soil; Rice crop; sowing dates; hybrid rice; Physiological characters; yield
Pages 178-183 PDF full Text
Table of Contents
DNA fingerprinting of rice (Oryza sativa L.) cultivars using microsatellite markers
Muhammad Shefatur Rahman, Md. Rezwan Molla, Md. Samsul Alam and Lutfur Rahman
Abstract
Microsatellite combines several features of an ultimate molecular marker and they are used increasingly in various plant genetic studies and applications. In this work, we report on the utilization of a small set of three previously developed rice microsatellite markers for the identification and discrimination of 17 HYVs and 17 local rice cultivars including two wild rice cultivars. All analyzed microsatellite markers were found to be polymorphic with an average number of 6.33 alleles per locus. These three markers were able to identify 15 local rice cultivars and 11 HYVs. A total of three variety specific alleles, RM-11/147, RM-151/289 and RM-153/178 were identified for BR-11, Badshabhog and BR-19 cultivars respectively. DNA fingerprints of rice cultivars by means of microsatellites provided meaningful data, which can be extended by additional microsatellite markers. The data obtained can be used for the protection of plant genetic resources.
Keywords: Rice; microsatellite; markers; variety identification
Pages 122-128 PDF full Text
Effect of integrated weed management on weed control and yield components of maize and cassava intercrop in a southern Guinea savanna ecology of Nigeria
Olorunmaiye Patience Mojibade and Olorunmaiye Kehinde Stephen
Abstract
The use of pre-emergence herbicides, hoe weeding and live mulch of herbaceous cover plants in a maize/cassava intercrop was investigated at the Teaching and Research Farm of the University of Ilorin, in 2002 and 2004. Experiment consisted of eight main treatments and six sub treatments. The main treatments which is the focus of this article were made up of the application of two pre-emergence herbicides [Primextra and Galex, each at 2.5 kg a.i./ha alone or with one or two supplementary hoe weedings at 6 weeks after planting (WAP) or 6 and 12WAP], a hoe-weeded check (hoeing at 3, 6 and 12WAP) and a weedy control. The experiment was laid out in a randomized complete block design with a criss-cross arrangement, and replicated three times. Data were collected for weed infestation and control, as well as for yield of food crops. When used alone, the pre-emergence herbicides gave satisfactory weed control up to 6WAP, but failed to give season-long weed control. However, better weed control was achieved when the pre-emergence herbicides were supplemented with two hoe-weedings, (P<0.05). Consequently, Primextra plus two hoe weedings (Prim+2HW) gave significantly lower weed biomass (42.9 g/m²) and higher yields of the food crops (1135 kg/ha for maize and 10,027 kg/ha for cassava) compared with the hoe-weeded control treatment (63.0 g/m², weed biomass; 849 kg/ha, maize and 8076 kg/ha, cassava), plots treated with Primextra alone (80.4 g/m², weed biomass; 678 kg/ha, maize; 1801 kg/ha, cassava) and the weedy control (116.3 g/m², weed biomass; 358 kg/ha, maize and 1425 kg/ha, cassava).
Keywords: weed; herbicides; savanna; yield; maize; cassava
Pages 129-136 PDF full Text
Effect of seed irradiation on the content of antioxidants in leaves of Kidney bean, Cabbage and Beet cultivars
N. Kacharava, Sh. Chanishvili, G. Badridze, E. Chkhubianishvili, N. Janukashvili
Abstract
Seeds of two varieties of kidney bean (Phaseolus vulgaris L., var. oratus and var. ellipticus), cabbage (Brassica oleracea L., var. capitata alba and var. capitata rubra) and beet (B. vulgaris L., saccharifera Alef. and ssp. esculenta (Salisb) Gurke, var. rubra) were exposed to ultraviolet (UV) irradiation (460-760 µW/cm2 for 30, 60 and 90 min). The purpose of the study was to evaluate the importance of pre-sowing treatment with UV for activation the antioxidative system and building up adaptive mechanisms against unfavorable environmental conditions in crops. In particular, we studied the effects of exposing seeds to UV irradiation prior to sowing on antioxidant contents in leaves of experimental plants developed from the irradiated seeds and on their physiological state and growth indices (height, biomass, photosynthetic activity of leaves, amount of plastid pigments and total proteins). Treatment of seeds with low doses of UV caused increase in ascorbic acid content in leaves of kidney bean varieties (32-35%). Applied doses of UV significantly enhanced the amount of tocopherol in leaves of both varieties of kidney bean (2-4 times and more), and white beet (5-9 times). Seed UV irradiation with high doses (90min) had clear effect on the content of plastid pigments in kidney bean varieties (about 35%), while in cabbage and beet stimulative were both doses (30min and 90min) (45% and more). UV treatment of seeds also stimulated synthesis of anthocyanins in leaves of kidney bean varieties (3-6%) and white beet (14-21%). In the case of cabbage and red beet low doses of irradiation were effective (9-20%). We conclude that UV irradiation of seeds stimulated stress adaptive mechanisms in tested plants. These effects, however, depend on the intensity of irradiation, also on plant species and varieties. Treatment of seeds with optimal doses of UV irradiation may used for stimulation of antioxidant synthesis in plants and enhance their nutritional value and tolerance to environmental stress factors.
Key words: anthocyanins; ascorbic acid; tocopherol; seeds; vegetables; ultraviolet irradiation
Pages 137-145 PDF full Text
Heterosis in yellow maize
AE Sharief, SE El-Kalla, HE Gado and HAE Abo-Yousef
Abstract
Ten new yellow maize inbred lines were top crossed to three testers i.e. Gm. 1021, S.C. 52 and Comp 21 at Gemmeiza in 2005 season. Thirty top crosses plus three checks were evaluated at Gemmeiza and Sids Agricultural Research Section, Egypt in 2006 season. Significant differences were noticed between the two locations for all the studied traits except resistance to late wilt disease. Mean squares due to crosses and their partitioning lines and testers were highly significant except 50% silking at Gemmeiza ,while lines x testers interaction were significant for plant height , ear height, resistant to late wilt disease and grain yield under two location and their combined ,while, it was significant for Gemmeiza of days to 50 % silking. At least nineteen crosses surpassed from the three checks (S.C.155, TWC. 352 and Gm.Y.Pop.) in yield potentiality. The highest mean performance were detected in the cross Gm. 3 x Gm. 1021 (15.090t/ha) followed by the cross Gm.1 x Gm. 1021 (14.640t/ha) and the cross Gm. 8 x Gm. 1021(13.731t/ha), respectively. These crosses are favorable and could be used in maize breeding programs.
Pages 146-154 PDF full Text
Genetic dissection of biomass production, harvest index and panicle characteristics in indica-indica crosses of Iranian rice (Oryza sativa L.) cultivars
Hossein Sabouri, Atefeh Sabouri, Ahmad Reza Dadras
Abstract
Improvement of rice (Oryza sativa L.) yield through breeding requires a good understanding of genetic factors that control component traits. In the current study, traits associated with this multiplicative relationship were investigated in a field trial with F2 and F2:3 population of rice. One-hundred-and-ninety-two individuals and families derived from a cross between two genetically divergent high-yielding varieties, Khazar (KHZ, indica type with a large biomass) and Tarommahalli (TAM, indica type with a low biomass), were grown in Rice Research Institute of Iran and Gonbad High Education Center to detect QTLs for biomass and related traits. Result of mapping on F2 population showed that QTLs controlling GWP (qGWP-3a and qGWP-3b) overlapped with the QTLs for number of SNP (qSNP-3a and qSNP-3b) and the QTL for HI (qHI-3). Five QTLs were mapped for harvest index. These QTLs were showed the large effects on the harvest index and explained 21.35 to 31.28% of the total phenotypic variance. Result of F2:3 population showed that QTLs controlling GWP (qGWP-2, qGWP-7 and qGWP-12) overlapped with the QTLs for number of SNP (qSNP-2, qSNP-7 and qSNP-12). Clustering of the QTLs for different traits at the same markers interval in both of mapping population was observed for GWP, HI and SNP. These result implied that HI, might partly share a common genetic basis with GWP and SNP. Our result indicated that breeding methods of QTLs pyramiding by using marker-assisted selection could be very useful for the development of new varieties with a high level of grain yield.
Keywords: biomass; grain yield; rice (Oryza sativa L.); QTL mapping.
Pages 155-166 PDF full Text
Combined effect of host plant resistance and insecticide application on the development of cowpea viral diseases
Z. Ambang, B. Ndongo, D. Amayana, B. Djilé, J. P. Ngoh, G.M. Chewachong
Abstract
Cowpea [Vigna unguiculata (L) Wap] is an important food crop which is widely grown in the Soudano-sahelian region of Cameroon. An integrated disease control approach involving insecticide treatment and plant host resistance was used to control virus-induced diseases, which are the most cowpea yield-limiting factor in this part of the country. A field experiment was conducted at Guirin-Maroua location in which three cowpea varieties (CRSP, LORI and VYA) that differ in their resistance to cowpea viral diseases were treated with Cyperdim 220 EC insecticide at different doses (1.75, 1.25 and 0.95 l/ha). In this experiment, severity of cowpea viral diseases including SMVD, YMVD, ABMVD and GMVD, were assessed. Population size of thrips (Megalurothrips sjostedti) and larvae of Maruca testuladis, two main vectors of cowpea viral diseases were evaluated. An evaluation of cowpea grain yield was also made. Visual diagnosis which was confirmed by ELISA test showed that only SMVD, YMVD, ABMVD were present during these investigations. Both viral diseases and the population of vectors reduced with combined treatment consisting of the less susceptible cowpea variety VYA and the highest insecticide dose (1.75 l/ha). This treatment combination also produced the highest cowpea grain yield (29.5 t/ha), a yield that was almost 3 times higher than the control (10.2 t/ha). Our results suggest that cowpea viral diseases that prevail in the Soudano-sahelian region of Cameroon are likely to be under control if less susceptible cowpea varieties such as VYA are treated with some insecticides including Cyperdim 220 EC.
Keywords: Cyperdim 220 EC; integrated management; natural defence; Vigna unguiculata; viruses
Pages 167-172 PDF full Text
In vitro effects of some pesticides on pathogenic fungi associated with legumes
Dare Michael Olajire and Fawole Oluyemisi B
Abstract
An in vitro effect of three pesticides commomly used in the southern Guinea savanna namely Benomyl (fungicide), Galex® (herbicide) and Karate® (insecticide) on the growth of three pathogenic fungi of legumes, Fusarium oxysporum, Aspergillus flavus and Fusarium monilliforme, was investigated to determine the effectiveness of the pesticides in reducing the growth of these fungi . Each fungicide was assayed with each fungus at 0, 100, 200, 400 and 500 mg L-1 rate in Potato Dextrose Broth (PDB) and incubated at 30°C for five days. Each treatment was replicated four times. Data were collected on the mycelia weights of the fungi under each treatment. Mycelia weights of the three fungi were significantly reduced at 100 mg L-1 by all the pesticides except that of A. flavus under Benomyl treatment where some resistance was observed. Significant reduction of mycelia weights of the three fungi was observed at 500 mg L-1 of Galex® application compared to other application rate of Galex. Application of Benomyl and Karate® significantly reduced mycelia weight of F. oxysporum irrespective of the rate applied. Growth of the two Fusarium species was completely inhibited by Benomyl at the application rate of 500 mg L-1. Galex® and Karate® which are herbicide and insecticide respectively, had detrimental effect on the tested pathogenic fungi of legumes and therefore may reduce incidence of diseases caused by these fungi in legume production in the southern Guinea savanna of Nigeria. We suggest that application of Karate or Galex can be effectively used to control some important pathogenic fungi of legumes.
Keywords: Aspergillus flavus; fungicide Fusarium monilliforme; Fusarium oxysporum; herbicide; insecticide; mycelial weight
Pages 173-177 PDF full Text
Physiological evaluation of some hybrid rice varieties under different sowing dates
Ali abdalla basyouni Abou khalifa
Abstract
A field experiment was conducted at the experimental farm of Rice research and training centre (RRTC), Sakha, kafr- El sheikh governorate, Egypt in 2008 rice season for physiological evaluation of some hybrid rice varieties under different sowing dates. Four hybrid rice H1, H2, GZ 6522 and GZ 6903 were evaluated at six different sowing dates, April 10th, April 20th, May 1st, May 10th, May 20th and June 1st. A split plot design with four replications was used as six sowing dates were allocated in the main plots, and four rice varieties in sub plots. Results indicated that early date of sowing (April 20th) is the best time of sowing for important properties such as maximum tillering (MT), panicle initiation (PI), heading date (HD), number of tillers per M2, plant height and root length at PI and HD stage, chlorophyll content, number of days to PI and HD, leaf area index, sink capacity, spikelets/ leaf area ratio, Number of grains per panicle, Panicle length (cm), 1000 grain weight (g), number of panicles per M2, five Panicle weight (g) and grain yield (T/ha). Sterility percent was the lowest value in April 20th sowing date. Sowing in 1st June has given the lowest value for all studied traits. H1 hybrid rice variety surpassed other varieties for studied characters except for number of days to panicle initiation and heading date.
Keywords: Normal soil; Rice crop; sowing dates; hybrid rice; Physiological characters; yield
Pages 178-183 PDF full Text
