Obituary - Dr. M.A. Bajwa
ABSTRACT:
Dr. Manzur Ahmed Bajwa, an eminent scientist, breathed his last on 16th June 1993 due to heart failure auhe Combined Military Hospital, Rawalpindi. May God Almighty shower His choicest blessings upon the departed soul. Ameen.

Chemotaxonomic studies of the genus Medicago L. (Papilionoideae) from Pakistan
ABSTRACT:
The flavonoid chemistry of 7 species belonging to 4 subgenera of the genus Medicago L, has been reported for the first time from Pakistan. The flavonoid pattern strongly support the infrageneric classification of the genus. It also seems to be useful to solve the problems at inter and infraspeciflc levels.

Effects of seed dispersal unit and the position of seed relative to substrate on germination of three composites
ABSTRACT:
Diaspore morphology has long been assigned a role for dispersal byvarious mechanisms. An experiment was designed to investigate the effect of dispersal unit and the position of seed relative to substrate on germination of three composites (Iphonia grantioides, Tridax procumbens and Sonchus arvensis). Seed morphology of the three species was studied and pappus appeared to influence the overall germination percentage. Diaspore having attached pappus and lying horizontally on the surface of the soil showed maximum germination compared to other positions. Diaspore having detached pappus and lying horizontally on the soil surface showed lower germination percentage than the seed with attached pappus. The angle of contact with soil is also important besides pappus which presumably regulates water absorption by seed and consequently the rate and overall germinat}on percentage.

RELATIVE EFFECT OF WEEDS ON TOPPING AND RATOONING RAPESEED (BRASSICA NAPUS L.)
ABSTRACT:
Experiments were conducted with Westar rapeseed (Brassica napus L) to determine the effect of weeds at different growth stages on topping dry matter and seed yield of ratooned crop. Dry matter yield of weed-free plots was greater than that of weedy plot; this was most pronounced with topping at the bud stage and at first flower. At the earlier topping stages, the crop dry matter was more than that of the oats, indicating greater early season growth of the rapeseed than of the oats. Early topping between pre-bud and bud stage allowed competition from the weeds for the longest period of time and resulted in the lowest seed yield and highest weed dry matter as compared to crop topped late at first flower (3/4 plant cut) or removal of secondary branches, even lowest in the check plots (un-topped). The removal of secondary branches produced highest seed yield over all treatments including check plots under both weedy and weed-free conditions but was worst for topping dry matter.

PERFORMANCE OF F1 HYBRIDS FROM VARIOUS PLOIDY LEVELS IN COTTON
ABSTRACT:
Studies were carried out for comparing the magnitude of heterotic expression in F1 hybrids from two ploidy levels i.e., pentaploid x tetraploid and tetraploid x tetraploid. The pentaploid hybrids expressed 22.18% average heterosis over mid parents whereas corresponding value in tetraploid hybrids was 14.17% for plant height. With respect of mid-lobe leaf length, the average increase of pentaploid hybrids against mid and better parents respectively were 22.82 and 6.30% while the corresponding values in tetraploid hybrids were 8.46 and 7.02%. In case of mid-lobe leaf width, pentaploid hybrids on an average, expressed heterosis of 35.74 and 10.33% respectively over mid and better parents as compared to 12.35 and 10.40% respectively in tetraploid hybrids over corresponding parents. On an average pentaploid crosses gave increased seed cotton yield of 136% against mid parents. Regarding ginning outturn percentage, the pentaploid hybrids produced maximum heterosis of 6.09 and 4.39% respectively, against mid and better parents while in tetraploid hybrids, corresponding values of 3.00 and 2.54% were recorded. Concerning staple length, hybrids from two ploidy levels did not show apparent differences.

COMPETITIVE INTERFERENCE BY SOME INVADER SPECIES AGAINST KALLAR GRASS (LEPTOCHLOA FUSCA) UNDER DIFFERENT SALINITY AND WATERING REGIMES
ABSTRACT:
Kallar grass [Leptochloa fusca (L.) Kunth] was grown in mono-cultures and in mixed-cultures with Suaeda fruticosa (L.) Forssk., Cynlodon doctylon (L.) Pers., and Sporobolus arabicus Boiss., under different soil salinity and water conditions. The biomass yield data indicated that Kallar grass is a weak competitor against S. fruticosa at high salinity and against C. doctylon at low salinity, while its growth was not affected due to competition by S. arabicus. However, the yield of Kallar grass in mono-cultures (2 plants/pot) was significantly higher than that in corresponding mixed-cultures (2 plants Kallar grass + 2 plants of weed/pot). Although Kallar grass growth was low in its mono-cultures with 4 plants/pot compared to 2 plants/pot, it suffered more severe' interference from weed species under certain conditions than from its own individuals. In general, at a particular salinity and watering treatment, nutrient concentrations in plant shoots of a species grown in mono- and mixed-cultures were similar. However, total uptake of nutrients (N,P,K,Ca and Na) by Kallar grass and competing species differed significantly and weed species removed proportionately higher amounts of nutrients in mixed-cultures. The significance of competitive interactions among species with regard to their coexistence and productivity in a common environment in saline areas is discussed.

EFFECT OF SALINITY ON GERMINATION AND GROWTH OF ALFALFA, SUNFLOWER AND SORGHUM
ABSTRACT:
The effect of different levels of salinities on germination and growth of alfalfa (Medicago sativa), sunflower (Helianthus annuus) and sorghum (Sorghum bicolor) plants was studied. NaCl and CaCl2 (1:1 w/w) @ 1000, 3000, 5000 and 7000 ppm in Hoagland solution were used. During germination stage, sunflower tolerated salinity upto 5000 ppm and alfalfa and sorghum upto 3000 ppm. During growth stage, dry matter, leaf area and pigment fractions in alfalfa and sunflower increased at low levels of salinity but decreased at higher levels. In sorghum plants growth parameters decreased at all the salinity levels.

CHLOROPHYLL MUTATIONS IN VIGNA RADIATA (L.) WILCZEK. II. MUTAGENIC EFFECTIVENESS AND EFFICIENCY OF CHEMICAL MUTAGENS
ABSTRACT:
Using EMS, MMS and SA, mutations were induced in two mungbean (Vigna radiato (L) Wilczek) varieties viz., PS-16 and Pusa Baisakhi. Three different types of chlorophyll mutants viz., albina, Chlorina and Viridis were observed in M2 generation. Chlorophyll mutation frequency increased with increase in concentration of various mutagens. EMS produced highest frequency of mutations followed by MMS and SA. On the basis of their effectiveness, three mutagens stood in the declining order of MMSSAEMS whereas on the basis of their efficiency, the sequence was EMS, MMS and SA. All the three mutagens were found to be effective and efficient at the lower mutagen concentrations.

SEASONAL PATTERN OF NODAL AND DIURNAL REPRODUCTIVE ABSCISSION IN THREE SOYBEAN CULTIVARS
ABSTRACT:
The nodal and diurnal abscission patterns in two determinate (Lee, MG Vi and Essex MgV) and one indeterminate (Williams MG III) cultivars of soybean (Glycine max (L) Merrill) were examined. Lee, Essex and Williams aborted 15.4, 6.7 and 3.2 flowers and 4.8, 1.8 and 1.6 pods per node, respectively. Total flower and pod abortion was 57.9 and 38.1% in Lee, 59 and 31.8% in Essex and 42.8 and 36.7% in Williams, respectively. Flower and pod abortion in the lower two-third canopy accounted for 77 and 83.4% in Lee, 83.8 and 61% in Essex and 88 and 84.6% in Williams, respectively. The period of blooming, pod setting and pod filling differed for different cultivars and even within the same cultivar. In Lee and Essex maximum reproductive abscission occurred during the first two-third of the period and in Williams during the middle.

EFFECTS OF ONTOGENETIC STAGES, LEAF POSITION AND COLOUR RATING ON CO2 ASSIMILATION IN PHASEOLUS VULGARIS L., UNDER FIELD CONDITIONS
ABSTRACT:
CO2 assimilation rate in beans (Phaseolus vulgaris L) was investigated under field conditions. The rate of CO2 assimilation in leaves was significantly affected by ontogenetic stages, leaf position and their interactions. Maximum CO2 assimilation rate (15.332 mg CO2/dm-2 hr-1 was recorded at flowering stage followed by budding whereas, among the leaf positions. the higher rate of (14.985 mg CO2/dm-2 hr-1 was observed in upper leaves followed by central and lower leaves. Both leaf area and dry matter accumulation was higher at the pod forming stage, highest CO2 assimilation was recorded in deep green leaves followed by light green and yellow leaves. CO2 assimilation rate drastically reduced after pod formation as the case with dry matter accumulation and leaf area. CO2 assimilation was maximum in upper as well as deep green leaves as compared to lower leaves with light green or yellow colouring.

SUITABILITY OF CASUARINA EQUISETIFOLIA WOOD FOR PULP AND PAPER INDUSTRY IN PAKISTAN
ABSTRACT:
Wood chemical constituents such as holocellulose, alphacellulose and lignin contents of Casuarina cqllisclifolia were investigated from extractive - free wood of trunks and branches. In trunk wood amount of holocellulose, alphacellulose and lignin wee 73.08±3.91, 46.41 ±4.49 and 26.32±3.71% respectively, whereas for branch wood the corresponding values were 72.14±: 2.20, 42.87± 2.66 and 27.73± 1.55% respectively. The average fiber length, fiber diameter and fiber wall thickness was 978.28±48.26 mm, 14.81±4.97 µ.m and 6.95±t2.86 µ.m respectively. The amount of holocellulose, alphacellulose and lignin in the trunk wood and branch wood when compared with other types of wood suggest that relatively high pulp yield can be obtained r rom them. However, short lengt h and small diameter of fibers would render Casuarina wood unsuitable for making strong paper.

IMPROVEMENT OF REGENERATION CAPABILITIES OF CALLUS DERIVED FROM SHOOT APICES OF PEANUT (ARACHIS HYPOGAEA L.) SEEDLINGS
ABSTRACT:
Shoot apices of peanut seedlings inoculated on MS medium containing 1 mg/I BA arid 0.01 mg/I NAA showed a prolific development of callus without differentiation after about 5 months of culture period with regular subcultures of one month. The calli regenerated plants when transferred to MS medium supplemented with 0.5 mg/I each of BA, 2 ip, Z and IAA (0.1 mg/I) after one month of culture. At least 10 plantlets/callus were obtained and the plantlets could be grown to adult stage under field conditions.

IN VITRO CLONAL PROPAGATION OF PAPAYA (CARICA PAPAYA L.)
ABSTRACT:
A procedure for the rapid clonal propagation of (Carica papaya L) was developed by culturing apices of mature field grown plants. The explants were successfully established on MS medium supplemented with 10 mg/1 kinetin and 2 mg/1 NAA. The growing explants upon transfer to a proliferation medium containing reduced levcls of BA (0.5 mg/1) and NAA (0.1 mg/1) produced maximum number of shoots per explant. Shoots rooted well in IBA supplemented MS medium and plantlets developed were transferred to soil.

CALLUS CULTURES OF ROSA HYBRIDA CVS., DIAMOND JUBLY AND LANS FRANCE
ABSTRACT:
Callus cultures were initiated from flower cups of cultivars of Rosa hybrida. Copious callus formation and growth was observed in cv. Diamond Jubly with 0.5 mg/l 2,4-D + 0.1 mg/1 kn and in cv. Lans France with 0.5 mg/1 2,4-D + 0.5 mg/I kn. Sodium diethyldithiocarbamate (SDC) at 250 mg/1 effectively controlled browning in cultures of both cultivars. SDC effect was related to concentration of phytohormones required by cultures at every 24 day cycle.

OBSERVATIONS ON TAONIA ATOMARIA F. CILIATA (LAMOUR.) NIZAMUDDIN
ABSTRACT:
Taonia atomaria f. ciliata (Lamour.) Nizamuddin is raised to specific level and designated as Taonia pseudo ciliata (Lamour.) Nizamuddin & Godeh comb. nov. characterized by twisted, linear, narrow, ciliatodentate, strongly marginally proliferated segments, in cell structure of the thallus which basipetally grades from (3-) 4-6(-8) layers and a single sporangial basal stalk cell partially embedded in the thallus.

A NEW SPECIES OF THE GENUS CODIUM (CHLOROPHYTA - CODIALES) FROM THE EASTERN COAST OF LIBYA
ABSTRACT:
A new alga, Codium tobrukense Nizamuddin & Fathalla sr. nov., and a new form, C. tobrukense f. eImasirelise Nizamuddin & Fathalla f. nov.,. are described from Tobruk in the eastern coast of Libya.

EFFECT OF VAM FUNGUS (GLOMUS INTRARADICES) ON THE GROWTH OF SORGHUM, MAIZE, COTTON AND PENNISETUM UNDER SALT STRESS
ABSTRACT:
Effect of VAM-fungus Glomus intraradices on the growth of sorghum, maize,.cotton and Pennisetum sp., was studied in soil under salt stress. The VAM-inoculated 20 day old seedlings growing in 1% (16.0m mho em-1) saline soil showed better growth and increase in fresh and dry weight over the non-inoculated plants.

EFFECT OF SEED PELLETING WITH BIOLOGICAL ANTAGONISTS IN THE CONTROL OF ROOT INFECTING FUNGI OF COWPEA AND MUNGBEAN
ABSTRACT:
Effect of seed pelleting with Stachyboays atra, Memnoniella echinata and Rhizobium meliloti on colonization of mungbean and cowpea roots by Macrophomina phaseolina, Rhizoctonio solani and Fusarium spp., was studied. A combined use of S. atra and R. meliloti was more effective in suppressing colonization of M. phaseolina and Fusarium spp., on mungbean and R. solani on cowpea roots than their separate use. Colonization of cowpea roots by all the three pathogens, and of mungbean roots by Fusarium spp., was greatly suppressed by a combined use of M. echinata and R. meliloti than their separate use. Use of S. atra showed greater phytotoxicity on cowpea as compared to mungbean.

DETECTION OF SEED-BORNE MYCOFLORA IN PINUS GERARDIANA
ABSTRACT:
Using agar plate, blotter and deep freezing method, 14 genera and 26 species of fungi were isolated from fourteen seed samples of Pinus gerardiana. About 70% of the samples were infected with Aspergillus flavus and A.niger with an infection range of 4 to 56% and 4 to 100% respectively. Agar plate method yielded greater number of fungi (19) as compared to deep freezing method (13) and blotter method (12). Deep freezing method was found superior to standard blotter and agar plate method for the detection of Altemaria, Cladosporium and Fusarium spp.

EFFECT OF TILLAGE PRACTICES ON THE POPULATION AND , VIABILITY ORSCLEROTIA OF SCLEROTIUM ORYZAE AND YIELD OF RICE
ABSTRACT:
Effect of tillage practices on population and viability of sclerotia of Sclerotium oryzae and yield of rice was examined. Maximum tillage showed complete loss in viability of sclerotia at 0-5 cm soil surface and at (15-20 cm) depth. Yield of rice increased by 59% in maximum tillage as compared to minimum and no-tillage treatments.

Effect of water stress on charcoal rot disease of mashbean (Vigna mungo (L.) Hepper) caused by Macrophomina phaseolina
ABSTRACT:
Mashbean (Vigna mungo L) Hepper) an important pulse crop of Pakistan is planted over 85,000 hectares giving an yield of 30- 40 thousand metric tonnes (Anon., 1990). Of the fungal, bacterial and viral diseases which produce an annual loss of 12-14% the charcoal rot caused by Macrophomina phaseolina (Tassi) Goid., produces 100% damage to the crop in severe cases (Bashir & Malik, 1988). The fungus infects the seedling, root, stem or pods producing small black sclerotia which are liberated in soil upon tissue decomposition or during tillage operation (Cook et al., 1973).

New records of Pythium species in Pakistan
ABSTRACT:
The genus Pythium Pringsh., includes many plant pathogenic species which cause damping-off and root rot disease on important crops resulting in severe losses (PlaatsNiterink, 1981). Although reports of fungi like Macrophomina phaseolina (Tassi) Goid, Rhizoctonia solani Kühn, Fusarium spp., Sclerotium spp., and Sclerotinia spp., attacking under ground parts of crop plants in Pakistan have been made (Mirza & Qureshi, 1978; Shahzad & Ghaffar, 1986, 1990; Shahzad et al., 1988), Pythium spp., have received little attention. Of over 120 species of Pythium (Dick, 1990), P. aphanidermatum (Edson) Fitzpatrick from Capsicum annuum L. and unidentified Pythium sp., from soil have been reported form Pakistan (Mirza & Qureshi, 1978). During a survey of cultivated fields in different parts of Pakistan, P. aphanidermatum and P. periplocum Drechsler were isolated and identified after reference to Plaats-Niterink (1981) and Dick (1990).