Detailed genetic retrospect , with respect to degree of dominance , nature of dominance , proportion of positive to negative effects of genes at the loci exhibition dominance , proportion of dominant to recessive genes in the parents and the number of groups of genes controllinh the particular character was studied for onset-of- heading. 75% heading , heading-span and plant height in a five-parent diallel cross of common wheat ( triticum aestivcum L.) for four generations at two locations in the university of alberta, Edmonton, Canada. The parents involved were marquis. Chinook ( both Canadian) . khushhal (Pakistan), ciano-67 and inta-66
Wheat crosses of nine medium and
dwarf varieties were evaluated for expression of heterosis in F1 generation for plant height , grain yield and its components. Viz, number of species per plant, number of grains per spike , number of spike,etc per spike and 1000- grain weight. In almost all the crosses, the heterotic effects were apparent in F1 generation to varying extent.
A sterile cold tolerant triploud of
gossypium hirsutum x G. nandewarence was obtained which is being reported for the first time in the history of cotton . cytological studies were carried out and
20.81, 8.611 and 0.33111 recorded at metaphase-1. Morphological studies showed that the hybrid was vigorous and luxuriant in growth with profuse branching and foliage , intermediate in most of the characters. The most important observation was that the foliage remained ever-green
throughout the year, even in the severe cold spell in winter season like G. nandewarence.
Italian ryegrass (lolium multiflorum L. ) is
a common grass species in many temperate parts of the world. Laboratiort and green house experiments showed that besides toxic roots exudates , water soluble toxins are also present. The present of toxins in root exudates and in the above ground parts of Italian ryegrass was confirmed during the soil leaching, soil
mulching experiments and artificial rain drip bioassays. These toxins are capable of significant inhibition of germination and growth of avena, bromus , lactuea and trificlim tested . the possible role of these toxin producing species in agronomy , vegetational dynamics and range land ecology is discussed .
These selective herbicies phordene ,
phordester and phenoxylene used as pre-sowing treatment were generalyy effective in killing the broad leaved weeds, but weeds appeared again in the wheat growing season . selective herbicides phenoxylene, 2,4-D amine,
Regeneration of taraxacum efficinate
weber.. root cutings in relation to carbon and nitrogen supply was studied . it was found that the application of
KNO3 promoted the growth of shoots and roots. Sucrose alone, promoted the root growth only slightly where as sucrose and KNO3 showed a pronounced effect on root growth.
Organ differentiation in undifferentiated taraxacum root callus did not occur . when sucrose , KNO3 or both was provided . however , roots and shoots were induced in the fresh phoem explants by altering the level of auxin (IAA) and cytokinin (Adenine). And the
The combined effect of hydrostatic
pressures varying from 200-800 atm
and temperatures ranging from 5 degree ti 25 degree C. was studied on the activity of alkaline phosphatase in delesseria sanginneria and focus vesiculosus. At temperatures between 5 degree C and 15 degree C the hydro
static pressure caused a decrease in the enzymic activity , at higher
temperatures however the activity was accelerated under the same pressure. The changes in the enzyme activity brought about by increased hydrostatic pressure at temperatures other than 15 degree C were greater in D. sanguinea as compared to F. vesiculosus , enzyme activity in enteromorphia linza, laminaria saccharina and phycodrys sinuosa could not be detected.
The incidence of mycorrhizas in the
roots and endogone spores in rhizospheres soil of 73 plants growing around university campus Islamabad was investigated . vesicular-arbuscular
mycorrhizas were of general occurrence in all lants examined except the members of the families
amaranthaceae, chenopodiaceae, palmae, zygophyllaceae, nyctaginaceae , oxalidaceae , vitaceae, celasteraceae .,
A new name abutilon alii S. abedin is
given for abutilon lanatum Hus. And
Baq. (1974) which is a later ( miquel ,
1849). Relationship with its allied
species i.e. A. pannosum ( Forst. F.) Schl.
Is also discussed.
