Kernel setting at the apical and sub - apical ear of older and newer Argentinean maize hybrids
Rainfed maize [Zea mays, L.] crops in temperate semi-arid regions with high inter-annual variation ofsummer precipitation, are commonly cultivated at low population densities. During seasons with favor-able conditions for plant growth [e.g., summer rainfalls above normal records], the number of kernelsof sub-apical ear can contribute significantly to total kernel number per plant [TKN]. However, there isno information of the determinant traits of kernel setting at sub-apical ear, or the effects of breeding onthese traits. We used a crop physiology model with an individual plant approach in attempt to describegenotypic differences in those traits related to kernel setting at the apical [KNE1] and the sub-apical ear [KNE2] of older and newer Argentinean maize hybrids. Four representative hybrids of the decades of 80 minutes, 90 minutes, 00 minutes and 10 minutes were cultivated during two growing seasons at three densities [4, 8 and 12 pl m-2]. Non-destructive techniques were used to estimate the growth rate of individual plant [PGRPC], apical [E1GRCP] and sub-apical [E2GRCP] ear during the period bracketing silking [critical period], biomass partitioning to reproductive sinks [E1GRCPPGRCP-1and E2GRCPPGRCP-1] and the efficiency to set kernels of the plant [TKN PGRCP-1] and the ears [KNE1E1GRCP-1and KNE2E2GRCP-1]. Differences among tested hybrids inKNE1 [ca. 400-600 k ear-1] were mainly determined by KNE1E1GRCP-1 [ca. 230-280 k d-1g-1] whilenewer hybrids had the highest E1GRCPPGRCP-1 [mayor than 0.50]. By contrast, hybrids had similar KNE2 [ca. 124 kear-1] due to their similar E2GRCPPGRCP-1 [ca. 0.08] and KNE2E2GRCP-1 [ca. 93 k d-1g-1]. These resultssuggest that breeding effect on TKN was mainly determined by KNE1E1GRCP-1and for the newest hybridthis trait did not interact with plant density. Hence, the newest hybrid exhibited a positive linear responseof TKN to PGRPC [r2= 0.82] reaching the highest TKN among hybrids at low, mid and high density. A betterperformance of maize crops at low densities could be obtained by breeding for E2GRCPPGRCP-1.
| Main Authors: | , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | MAIZE, KERNEL NUMBER, APICAL EAR, SUB APICAL EAR, BIOMASS PARTITIONING, |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=47355 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= |
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