Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.06

ASSESSING GENETIC VARIATION FOR FLAG LEAF CHLOROPHYLL CONTENT IN DURUM WHEAT GERMPLASM

POMARICO M., PROCIDA T., FIGLIUOLO G., SPAGNOLETTI ZEULI P.L.

Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, Università degli Studi della Basilicata, Potenza.

germplasm, flag leaf, SPAD

One of the most important goals upon a breeding point of view for durum wheat, is to combine high protein content with yield stability in Mediterranean environment.

As chlorophyll content in the flag leaf has been shown to be correlated, under rainfed conditions, with grain protein content and thus with semola quality, a germplasm population composed by 57 lines from a world core collection and 124 RILs (Recombinant Inbreed Lines) from an intra-specific cross (between var. Creso and the genetically differentiated line CI5014), have been evaluated in Southern Italy (Gaudiano di Lavello-Potenza).

The chlorophyll content in the flag leaf, measured at anthesis, as SPAD (Soil-Plant Analysis Development) values (taken with the portable Minolta SPAD-502 chlorophyll meter), was compared, within the core of 57 lines, with yield trait components of the spike and with the overall genetic diversity detected with 61 RFLP probes.

SPAD average values ranged from a minimum of 42.2 to a maximum of 53.3 for the sample of lines and from 44.1 to 56.9 for RILs, while RILs parents were significantly different, with average values of 55 for Creso and of 49.5 for line CI5014, respectively. RILs revealed transgressive segregation for SPAD values.

The trait was negatively correlated with the “spike length” (r=-0.40 and P<0.002) and with "plant height" (r=-0.26 and P=0.05), while no correlation was detected with other yield trait components of the spike (n° of kernels, n° of nodes and kernels weight/spike).

SPAD showed a broad sense heritability of H²=0.6 using, as population, the germplasm lines and of H²=0.45 using, as plant materials, RILs and their parents. The last is almost only the additive component of genetic variance.

None relationship was found between genetically differentiated groups, revealed by RFLPs, and SPAD values.

Thanks to its good heritability and to the presence of "transgressive segregant genotypes", chlorophyll content in the flag leaf, under rainfed situations, can significantly improve the genetic progress in breeding programs and it can be useful for a fast and cheap screening and detection of durum wheat genotypes with high grain protein content in drought-stressed Mediterranean environments. However, considering that increases in protein content are negatively correlated with yield, for a breeding program, emphasis should be given to those genotypes combining high and stable yield with good quality.