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 - 4.19

Evaluation of yield stability and yield potential of barley genotypes cultivated in South Italy under rainfed conditions and in presence of supplemetary irrigation

stanca a.M.*, alberici R.*, Badeck F.W.**, Li destri nicosia O.***, GROSSI M.*, Delogu G.*

*) Istituto Sperimentale per la Cerealicoltura, Via S. Protaso 302, 29017 Fiorenzuola d’Arda (PC)

**) Potsdam Institute for Climate Impact Research (PIK) PF 60 12 03, 14412 Potsdam (Germany)

***) Istituto Sperimentale per la Cerealicoltura, SS 16 Km 675, 71100 Foggia

Hordeum vulgare, drought, genotype, SWSI

In Foggia (South Italy) three experiments have been carried out in 1999, 2000 and 2001 under irrigated (I) and non irrigated (NI) conditions. The mean rainfall in Foggia was 450 mm, with 250 mm received on average during the barley growing seasons. For the I trials the supplementary irrigation consisted in 80 mm of water distributed per year. About 100 genotypes were evaluated every year in trials with 3 replications, 89 genotypes were included in all the experiments.

The following traits were recorded in all plots: days to heading, plant height, yield, 1000 kernel weight; the kernel number/m² has been calculated.

The climatic conditions occurring during each of the three seasons had significant effects on barley productivity. However, the impact of drought was more relevant during the first and the third year, as shown by the reduction of grain yield (26%) in both season 1999 and 2001 compared to the 2000 (18%). For each year and treatment a Seasonal Water Stress Index (SWSI) has been calculated on the basis of the daily potential and actual evapotranspiration (estimated using the Thorntwaite method) occurred during each growing season. The level of grain yield has been analysed as a function of the SWSI, showing a clear linear regression. This regression may be employed to summarise the behaviour of each genotype across the different years and treatments by plotting its grain yield in function of the SWSI, and analysing the slope as a measure of the yield stability and the intercept as a measure of potential yield.

The effect of drought on the single genotype was then studied considering that the “ideotype” for drought land should have high yield both in rainy as well as in dry years. A group of genotypes ranked in the first class of significance: ‘Nure’, ‘Tea’, ‘Apex’, ‘Vertige’, ‘Magda’, ‘Formula’, ‘Tidone’, ‘Kelibia’ and ‘Majestic’. The high performance of these genotypes was confirmed by their presence among the best in both, irrigated and non-irrigated trials, with the exception of ‘Magda’ which had the highest yields under rainfed conditions, but not under irrigated conditions. Other genotypes, like 'Solen' and 'Cheri', were among the best under irrigation, but their yield was highly affected under rainfed conditions suggesting that they have a high yield potential but low yield stability. Few cultivars were almost unaffected by drought in terms of yield ('Elan', 'Canoro', 'Gaiano') however, with the exception of 'Elan', their productivity under favourable environments was very low. These cultivars represent a group of genotypes resistant to a mild drought stress, but with a limited yield potential.

The identification of genotypes with high yield potential and high yield stability suggest that selection under favourable environment may be employed to individuate genotypes adapted to middle water stress conditions.