Collection and evaluation of pearl millet (Pennisetum glaucum) germplasm from the arid regions of Tunisia

Pearl millet (Pennisetum glaucum (L.) R. Br.) is the most important summer cereal crop in the arid regions of Tunisia. A total of 283 accessions from 18 landraces were collected during the growing season of 1997 and evaluated in vivo at IRA, Benguerdane (during growing season 1998). Landrace (populations) grown by the farmers were shown to be mixtures of several types. Considerable variation was observed for all characters studied according to the descriptors developed by IBPGR and ICRISAT (1993). Time to flower varied from 30 to 66 days after sowing. Plant height ranged from 59 to 314 cm with a mean of 197.86 +/- 0.43. Number of tillers varied between 0 and 19 per plant. Considerable variation in spike shapes was observed. Frequency distribution analysis of different spike shapes shows predominance of lanceolate (23.7%) followed by oblanceolate (23.5%) over cylindrical (18.3%), conical (15.7%), candle (8.7%), spindle (6.6%), club (3.1%) and globose (0.3%) types. The landraces collected mostly produced large, grey-coloured, obovate seeds, with partly corneous endosperm. Analysis of variance (ANOVA) was performed to evaluate variation amongst the different landraces. The differences are highly significant at (alpha = 0.05) for all characters studied. Duncan analysis and hierarchical clustering were carried out to (1) estimate resemblance between provenances; and (2) group landraces into homogeneous classes (clusters). The resulting dendrogram shows three principal clusters regrouping landraces according to their geographical origins or farming conditions. Pearl millet germplasm from Tunisia's arid region presents a wide range of genetic variability. It can be used as a starting basis for breeding programmes to select high yielding varieties tolerating adverse arid conditions.