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Comparison of selection traits for effective popcorn (Zea mays L. var. Everta) breeding under water limiting conditions
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Orientador(es)
Resumo(s)
Climate change is expected to intensify water restriction to crops, impacting on the yield
potential of crops such as popcorn. This work aimed to evaluate the performance of 10
field cultivated popcorn inbred lines during two growing seasons, under well-watered
(WW) and water stressed (WS) (ysoil≥ −1.5 MPa) conditions. Water stress was applied by
withholding irrigation in the phenological phase of male pre-anthesis. Additionally, two
contrasting inbred lines, P7 (superior line) and L75 (low performer) were compared for
grain yield (GY) and expanded popcorn volume (EPV), selected from previous studies,
were tested under greenhouse conditions. In the field, no genotype x water condition x
crop season (G×WC×CS) interaction was observed, whereas GY (−51%), EPV (−55%)
and leaf greenness (SPAD index) measured 17 days after anthesis (DAA) (> −10%) were
highly affected by water limitation. In general, root traits (angles, number, and density)
presented G×WC×CS interaction, which did not support their use as selection
parameters. In relation to leaf senescence, for both WS and WW conditions, the
superior inbred lines maintained a stay-green condition (higher SPAD index) until
physiological maturity, but maximum SPAD index values were observed later in WW
(48.7 by 14 DAA) than in WS (43.9 by 7 DAA). Under both water conditions, negative
associations were observed between SPAD index values 15 and 8 days before anthesis
DBA), and GY and EPV (r ≥ −0.69), as well as between SPAD index 7, 17, and 22 DAA,
and angles of brace root (AB), number of crown roots (NC) and crown root density (CD), in
WS (r ≥ −0.69), and AB and CD, in WW (r ≥ −0.70). Lower NC and CD values may allow further root deepening in WS conditions. Under WS P7 maintained higher net
photosynthesis values, stomatal conductance, and transpiration, than L75. Additionally,
L75 exhibited a lower (i.e., more negative) carbon isotope composition value than P7
under WS, confirming a lower stomatal aperture in L75. In summary, besides leaf
greenness, traits related to leaf photosynthetic status, and stomatal conductance were
shown to be good indicators of the agronomic performance of popcorn under
water constraint
Descrição
Original Research
Palavras-chave
carbon isotope composition (d13C) drought leaf gas exchanges popcorn yield water use efficiency
Contexto Educativo
Citação
Kamphorst SH, Amaral Ju´ nior ATd, de Lima VJ, Santos PHAD, Rodrigues WP, Vivas JMS, Gonc¸alves GMB, Schmitt KFM, Leite JT, Vivas M, Mora-Poblete F, Vergara-D´ıaz O, Araus Ortega JL, Ramalho JC and Campostrini E (2020) Comparison of Selection Traits for Effective Popcorn (Zea mays L. var. Everta) Breeding Under Water Limiting Conditions. Front. Plant Sci. 11:1289
Editora
Raul Antonio Sperotto, Universidade do Vale do Taquari-Univates, Brazil