Hal/::'.lJerSymposrum. Book ofAbstracts - core.ac.uk · Twenty-two materiais were used: 10hybrids...
2
Hal/::'.lJer Symposrum. Book of Abstracts Performance of Selected and Non-Selected Maíze Hybrids for Short ASI under Moisture Stress M.X. Santos, CL.T. Andrade. .-\.C Oliveira, CE.P. Leite, E.E.G. Gama, H.WL Carvalho, CA.P. Pacheco, P.E.O. Cuimaracs, .md S.N. Parentoru Maize and Soq~hum National Research Center, Zip Code 151, 35701-970,Sete Lagoas-MG, Brazil lntroduction The use of tolerant gcnotypes has been suggested as the solution for increasing yíeld under drought conditions, one of the main limitations to com productíon, According to Santos et ai. (1997),these losses in Brazil may vary from 14 % to 28%, while Edmeades et al, (1989) estimated that 809'0of the com planted in tropical areas suffered 10% to 50% yield loss. Bolados et ai. (1993) indicated that the anthesis silk interval (ASI) is an easy-to-measure characteristic associated negatively with production understress conditions. Betrán et aI. (1997) recommended that inbred lines should present short ASI in order to obtain acceptable yield hybrid performances. Methods "wo separate experiments were evaluated: one with moisture stress during flowering/ grain filling and "-one under normal irrigalion. A conventional sprinkler system with the lateral fixed was used, Irrigation depths were measured using catch canso At the stress plot, irrigation was interrupted on the 55th day after planting (dap) and reinitiated at 90 dap. The applied írrigation sbeets were measured in batteries of 16 co11ectors installed in each experiment. In order to quantify the stress, soil-water content was monitored using gravimetric mcthods (Fig. 1). Samples were collected at depths of 0-20,20-40 and 40~ centimeters. Twenty-two materiais were used: 10 hybrids not selected for anthesis silk interval (NSASI), 5 hybrids with a11parental inbred Iines selected for short ASI (100% AS!),5 hybrids wíth one parental inbred lirte with short ASI (50% ASl) and two eommerdal checks (data not shown). In both tria1sthe experimental design was a randomized complete block with three replications. Results A strong moisture stress in the O to 20 em layer of the soil profile was observed (Fig. 1), where possibly much of the crop's root system was concentrated. The treatments with 1001••ASI generally showed a mean value of zero, and some treatments showed protogyny in both environments (data not shown). The mean yield values indicated some promising hybrids (data not shown) in both moisture stress and non- stress condilions (d ual purpose). The results indicated that ear number under stress (ENCS) seems to be associated with drought toleranee and this eould be used as a selection criterion along with ASL '- Conclusions Hybrids not selected for short AS! showed a 62% mean yield reductíon, while those selected forshort ASI showed 44.8 % to 54 ro mean yield reduction (100% ~I and 50% ASI, respectively) and were less sensitive to moisture stress during the flowering/ grain filling period. Higher mean yields of hybrids with short ASI in stress conditions seem to be more associated with lhe ear number than with ASL References Betran, F.J. et al, 1997. Proc. of 27lh Conf Genet, Biotech, and Breeding. Creece. Bolados, J. pt aI. 1993. Field Crops Research 31: 269-286. Edmeades, G.O. et aI. 1989. In F.W.G. Baker. Drought Resistanee in Cereais. Paris. Pp. 25-72. Santos, M.X. 1997. ln Proc Symp Developing Drought and Low N-Tolerant Maize. El Batán. 68
Transcript of Hal/::'.lJerSymposrum. Book ofAbstracts - core.ac.uk · Twenty-two materiais were used: 10hybrids...
Hal/::'.lJer Symposrum. Book of Abstracts
Performance of Selected and Non-Selected Maíze Hybrids for Short ASI under Moisture Stress
M.X.Santos, CL.T. Andrade. .-\.C Oliveira, CE.P. Leite, E.E.G. Gama, H.WL Carvalho, CA.P. Pacheco,P.E.O. Cuimaracs, .md S.N. Parentoru
Maize and Soq~hum National Research Center, Zip Code 151, 35701-970,Sete Lagoas-MG, Brazil
lntroductionThe use of tolerant gcnotypes has been suggested as the solution for increasing yíeld under droughtconditions, one of the main limitations to com productíon, According to Santos et ai. (1997), these lossesin Brazil may vary from 14 % to 28%, while Edmeades et al, (1989) estimated that 809'0of the com plantedin tropical areas suffered 10% to 50% yield loss. Bolados et ai. (1993) indicated that the anthesis silkinterval (ASI) is an easy-to-measure characteristic associated negatively with production understressconditions. Betrán et aI. (1997) recommended that inbred lines should present short ASI in order to obtainacceptable yield hybrid performances.
Methods"wo separate experiments were evaluated: one with moisture stress during flowering/ grain filling and
"-one under normal irrigalion. A conventional sprinkler system with the lateral fixed was used, Irrigationdepths were measured using catch canso At the stress plot, irrigation was interrupted on the 55th dayafter planting (dap) and reinitiated at 90 dap. The applied írrigation sbeets were measured in batteries of16 co11ectors installed in each experiment. In order to quantify the stress, soil-water content wasmonitored using gravimetric mcthods (Fig. 1). Samples were collected at depths of 0-20,20-40 and 40~centimeters. Twenty-two materiais were used: 10 hybrids not selected for anthesis silk interval (NSASI), 5hybrids with a11parental inbred Iines selected for short ASI (100% AS!),5 hybrids wíth one parentalinbred lirte with short ASI (50% ASl) and two eommerdal checks (data not shown). In both tria1stheexperimental design was a randomized complete block with three replications.
ResultsA strong moisture stress in the O to 20 em layer of the soil profile was observed (Fig. 1), where possiblymuch of the crop's root system was concentrated. The treatments with 1001••ASI generally showed amean value of zero, and some treatments showed protogyny in both environments (data not shown). Themean yield values indicated some promising hybrids (data not shown) in both moisture stress and non-stress condilions (d ual purpose). The results indicated that ear number under stress (ENCS) seems to beassociated with drought toleranee and this eould be used as a selection criterion along with ASL
'- ConclusionsHybrids not selected for short AS! showed a 62% mean yield reductíon, while those selected forshort ASIshowed 44.8 % to 54 ro mean yield reduction (100% ~I and 50% ASI, respectively) and were less sensitiveto moisture stress during the flowering/ grain filling period. Higher mean yields of hybrids with shortASI in stress conditions seem to be more associated with lhe ear number than with ASL
ReferencesBetran, F.J. et al, 1997. Proc. of 27lh Conf Genet, Biotech, and Breeding. Creece.Bolados, J. pt aI. 1993. Field Crops Research 31: 269-286.Edmeades, G.O. et aI. 1989. In F.W.G. Baker. Drought Resistanee in Cereais. Paris. Pp. 25-72.Santos, M.X. 1997. ln Proc Symp Developing Drought and Low N-Tolerant Maize. El Batán.
68
&eedmg For Abiotlc Stresses
~a>.•..•C'l
~ 25O
CJ) 20
15 Ipwp ~:-------------------
10 l- ~------------~--~--_.--------~---J50 70 75 80 85 90 956555 60 100
100
Days After Planting (day)
110
100-E 90E-E 80OO~
70 1I
O~Q)- 60C'l3:I
O
:: 1CJ)
[PWPJ3050 55 60
Fulllrrigated
75 80 8565 70 90 95
Figure 1. Soil-water storage along maize cyclesubmitted to fullinigation and with waterstress duringflowering. Janaúba, MG, Brazil, 2000.
Days After Planting (day)
69
