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Title: DETECTION OF QTLS FOR VERTICAL ROOT PULLING RESISTANCE IN MAIZE AND OVERLAP WITH QTLS FOR ROOT TRAITS IN HYDROPONICS AND FOR GRAIN YIELD UNDER DIFFERENT WATER REGIMES

Author
item LANDI, P - UNIV OF BOLOGNA
item SANGUINETI, M - UNIV OF BOLOGNA
item Darrah, Larry
item GIULIANI, M - UNIV OF BOLOGNA
item SALVI, S - UNIV OF BOLOGNA
item CONTI, S - UNIV OF BOLOGNA
item TUBEROSA, R - UNIV OF BOLOGNA

Submitted to: Maydica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2002
Publication Date: 12/1/2002
Citation: LANDI, P., SANGUINETI, M.C., DARRAH, L.L., GIULIANI, M.M., SALVI, S., CONTI, S., TUBEROSA, R. DETECTION OF QTLS FOR VERTICAL ROOT PULLING RESISTANCE IN MAIZE AND OVERLAP WITH QTLS FOR ROOT TRAITS IN HYDROPONICS AND FOR GRAIN YIELD UNDER DIFFERENT WATER REGIMES. MAYDICA. 2002. v. 47. p. 233-243.

Interpretive Summary: Strength of a corn root system can be estimated by vertical root pulling resistance (VRPR). However, this measurement is both laborious and destructive. It would be desirable to identify related traits whose measurements are easier and non-destructive. We examined the possibility of studying root strength without resorting to VRPR and whether conducting marker-assisted selection for VRPR would be beneficial. One-hundred-eighteen F3 families derived from Italian inbred lines Lo964 x Lo1016 were evaluated for VRPR in Missouri, for root traits in hydroponics in Italy, for grain yield under well-watered and water-stressed conditions, and for a drought tolerance index in Italy. We identified several quantitative trait loci (QTLs) for root strength as measured by VRPR. Many of these QTLs were also common with QTLs affecting root traits in hydroponics and/or yield traits under different water regimes. This information will be important to corn breeders in their attempts to increase root strength by selecting for related traits and to other plant scientists designing more productive crop plants through classical plant breeding.

Technical Abstract: Vertical root pulling resistance (VRPR) is a trait used to estimate root strength in maize (Zea mays L.). Its measurement is laborious and destructive; hence, we examined the possibility of studying root strength without resorting to VRPR and whether conducting marker-assisted selection for VRPR would be beneficial. The objectives of this investigation were: to identify the chromosomal segments (quantitative trait loci, QTLs) controlling VRPR; to study the coincidence of QTLs for VRPR and QTLs for both root traits in hydroponic culture and for grain yield under well-watered (GY-WW) and water-stressed (GY-WS) conditions; and to develop strategies for marker assisted selection at the detected QTLs. One-hundred-eighteen F3 families derived from Lo964 x Lo1016 were evaluated for VRPR (three locations, one year), for root traits in hydroponics (one trial), for GY-WS, GY-WW (one location, two years), and for a drought tolerance index (DTI) calculated as the ratio between GY-WS and GY-WW. For VRPR, 19 QTLs were detected in at least one location or for the mean across locations. Additive effects were positive for some QTLs and negative for others, consistent with the observed transgressive segregation. Eleven of the detected QTLs coincided (i.e., their peaks were within a 10 cM interval) with at least one QTL for root traits in hydroponics. Two QTLs on chromosome 1, peaking near csu145 and between PGAMCGT400 and PGAMCTA205, coincided with QTLs for three root traits in hydroponics. Eleven of the 19 QTLs for VRPR coincided at least once with QTLs for GY-WW, GY-WS, and/or DTI. Three of the coincident QTLs showed consistency of sign of additive effects for VRPR and for GY-WW, GY-WS, and DTI; two of these QTLs were on chromosome 1 and coincided with root traits in hydroponics. Our results suggest that marker assisted selection can utilize these two QTLs to improve both root characteristics and yield performance under WW and WS growing conditions.