The forgotten, ancient olive trees of the Spanish northwest: A first molecular and botanical analysis

No country has a larger area under olive (Olea europaea subs. europaea var. europaea) cultivation than Spain. In the Spanish northwest, however, this crop has largely been forgotten, even though olive oil was once an important product of the area. Sadly, apart from a few scraps of information handed down orally, little information exists regarding the genotypes grown, or from where they may have originally come. Many centuries-old olive trees, however, can still be found in the area, some even forming groves now part of open woodland but which may harbour an important genetic reservoir. The present work describes a botanical and molecular analysis of these ancient trees, following a survey of allegedly native genotypes surviving in different locations in Galicia. Comparison of their molecular profiles with those in the World Olive Germplasm Bank of Cordoba, and those in the database compiled by the Agronomy Department of the University of Cordoba, revealed two known Galician genotypes, ´Brava Gallega´ and ´Mansa Gallega´, and the Portuguese genotype ´Cobrancoça´. Six genotypes present in neither database were also detected. In addition, some misidentifications of the ´Mansa´ genotype in recent studies were clarified. Botanical analysis confirmed the molecular results in all cases. The findings suggest a larger survey should be performed so that the full olive genetic diversity of this region can be recorded and preserved.

Pasture and tussock responses to a single application of nitrogen or a full development process for drier hill country over two years

Increasing production from drier hill country to maintain economic viability must be balanced with environmental impacts and the preservation of the tussock landscape. This trial investigated the use of a one-off autumn application of nitrogen (100 kg N/ha) to increase pasture production from drier hill country over subsequent seasons while maintaining the tussock biota. Comparative controls and previously oversown blocks were included. The response to nitrogen in the first winter-spring period was approximately 13 kg DM/ kg N applied with no measurable response occurring thereafter. The oversown block produced around 3200 kg/DM/annum more than the other blocks, as expected in the first two years. The botanical analysis showed that browntop reinvasion of recently oversown pasture was rapid, increasing to a presence of over 50% in three years. Tussocks decreased in size in the nitrogen treated block, but this was possibly due to management practices rather than a response to fertiliser nitrogen. This trial highlights some of the issues that surround the optimal use of nitrogen fertiliser in drier hill country and also documents the invasion of less desirable grasses into the preferred developed pastures. Keywords: Nitrogen, tussocks, oversowing

Evaluation of the dry weight rank method for botanical analysis of grassland by means of simulation

With the Dry Weight Rank (DWR) method of 't Mannetje and Haydock [see Journal of British Grassland Society (1963) 18, 268-275] for botanical analysis in pastures, the dry weight proportions of species are estimated from their first, second and third ranks in dry weight in single quadrats. The yield correction of Haydock and Shaw [see Australian Journal of Experimental Agriculture and Animal Husbandry (1975) 15, 663-670] is used additionally to solve the problem of the respective under- and overestimates of the dry weight proportions of high and low yielding species when these grow in patches. In this paper the DWR method is evaluated by means of computer simulation. Main element of the simulation model is a computer sampling program with which a fictitious vegetation can be sampled with a circular quadrat. The output shows that the DWR method works well using relatively small sampling quadrats with, on average, only a few plants per quadrat, irrespective of the horizontal vegetation structure. In vegetations where species grow patchwise, satisfactory results are also obtained using large quadrats with much more plants (i.e. tens) per quadrat. The reason is that in these cases also minor species can compete successfully for first, second and third ranks. However, it appeared that only a certain degree of patchiness is necessary, and with the usually applied quadrat sizes up to 25 dmsuperscript 2, probably in most vegetations this condition is fulfilled. Care should be taken in applying the DWR method for estimating species composition in recently sown grasslands where species usually occur more or less at random. In those cases, in principle a very small sampling quadrat (smaller than 1 dmsuperscript 2) could be used. However, this has practical limitations since the quadrat size should not be too small for realistic yield estimations, needed for the Haydock & Shaw yield correction. The simulations revealed that one condition (i.e., that the sampling quadrat should be at least as large that it usually contains three or more species) is not necessary because of the almost always perfect functioning of the correction for missing ranks. Generally speaking, a sampling quadrat should be chosen not larger than is strictly necessary from the viewpoint of horizontal vegetation structure and from the viewpoint of realistic yield estimations. Multipliers calculated from simulation data could satisfactorily mimic the original multipliers of DWR given by 't Mannetje & Haydock. It is postulated that the DWR method is well suited for studying vegetation changes in old, floristically diverse grasslands with dominant species often in moderate dry weight proportions and species usually growing in patches.