Genotypic variation in abscisic acid (ABA) accumulation in artificially water-stressed maize leaves and its relationship with the ABA content in drought-stressed field conditions

English. Abscisic acid (ABA) accumulation was investigated in 34 maize (Zea mays L.) inbred lines subjected to an artificial water deficit by means of a detached-leaf test (DLT) applied to cabinet-grown plants. Significant differences for ABA content were found among 23 lines of the medium-maturity group, while no significant differences were detected among 11 lines of the early-maturity group as well as between the two groups. The coefficients of genetic determination (H2) estimated for ABA accumulation in the detached leaves were lower than those estimated in a previous field experiment in which ABA content had been investigated in the same lines under naturally-occuring drought conditions. In both maturity groups, no significant association was found between ABA values measured in detached leaves and those measured in the field. Therefore, ABA accumulation as measured in the DLT does not seem to be suitable trait for selection of genotypes differing in ABA content under conditions of drought stress in the field

Italian. [Si e' studiato l'accumulo di acido abscissico (ABA) in 34 linee consanguinee di mais (Zea mays L.) sottoposte a una artificiale carenza d'acqua per mezzo di un test su foglie staccate (DTL) applicato a piante cresciute in cella climatica. Si sono riscontrate differenze significative quanto al contenuto di ABA tra 23 linee del gruppo a maturazione media, mentre non sono state riscontrate differenze significative tra 11 linee del gruppo a maturazione precoce come pure tra i due gruppi. I coefficienti di determinazione genetica (h2) stimati per l'accumulo di ABA in foglie staccate risultavano piu' bassi di quelli stimati in un precedente esperimento in campo in cui il contenuto di ABA era stato determinato nelle stesse linee in condizioni naturali di siccita'. In entrambi i gruppi non e' stata riscontrata alcuna associazione significativa tra i valori di ABA misurati in foglie staccate e quelli misurati su campo. Pertanto, l'accumulo di ABA misurato in DLT non sembra essere un carattere adeguato per la selezione di genotipi che differiscono per contenuto di ABA in condizioni di stress da siccita' in campo]