From a preliminary study it was concluded that the % of alpha-pinene in the turpentine was a most satisfactory character for discriminating Pinus radiata, P. attenuata and their F1 hybrids, and it was suggested that the phenotypic differences might be regulated by a polygenic system [cf. F.A. 21...

Data from selfed progeny trials suggest that trees whose selfings have good form and vigour tend to produce better outcrosses than those whose selfings perform poorly. Benefit might come from a programme of inbreeding and outbreeding like that used for maize. KEYWORDS: Botany general \ tree...

Green Wattle (a) flowers in July and August and the seed ripens in 4-6 months, whereas Black Wattle (b) flowers in September and October, but the seed does not ripen until 12-14 months later. The shorter seed-ripening period of (a) is completely dominant in (a) X (b) hybrids, irrespective of the...

Tetraploidy has been induced in Black Wattle by treatment of the seed with colchicine solutions. The most suitable concentration of colchicine appears to be 0.02-0.03% for 24 hours' treatment, or 0.01-0.02% for 48 hours. Tetraploids can be distinguished from diploids by measurements, at an early...

An experimental approach to the study of polymorphism in Cupressus lusitanica has already yielded useful information on variation in seedlings of different origin. Observations so far support the views of Martinez on the geographic and taxonomic distinctions between the forms in Mexico known as C....

Demonstrates a method of evaluating tree-improvement programmes to answer the questions: 'How much genetic improvement is needed to justify the progeny-test approach? ', 'How does one determine which of two species would be improved at the greatest profit? ', and 'How much return can be expected...

The investigation [cf. F.A. 27 No. 193] has been continued. In 130 trees examined, sp. gr. and fibre length at comparable positions in comparable years have varied from 0.246 to 0.374 and 2.17 to 3.69 mm. respectively. Although some of this variation is not attributable to genetic differences,...

The first methoxy flavonoid compound to be reported in Black Wattle has been found in the leaves of ca. 8% of the trees in a normal population. The substance appears to be 4'-O-methyl-myricitrin, and has been named 'mearnsitrin'. Examination of available genetic material revealed that the...

In crossing trials between various strains of Acacia mearnsii, parent trees whose progeny showed resistance to gummosis in the early stages of growth, and others whose progeny were very susceptible to the disease, were recognized. KEYWORDS: Acacia mearnsii A. decurrens var. mollissima, A....

After 2 years in the field, with an average height of ca. 6 ft., this hybrid (P. elliottii X P. caribaea) has a 20% height advantage over both parents. The promise of hybrid vigour with intermediate stem form makes this cross of particular interest. KEYWORDS: Botany general \ biosystematics \ ...