EXTRACTION OF ANCESTRAL CONSTITUENTS OF NATURAL POLYPLOIDS. I. PRODUCTION OF PENTAPLOIDS (AABBD) FOR EXTRACTING THE TETRAPLOID (AABB) COMPONENT OF THE HEXAPLOID, TR1T1CUM AESTIVUM
ABSTRACT:
o extract ths ancestral tetraploid component, AABB, of the allohexaploid, Triticum aestivum (2n-6x 42), AABBDD, it is necessary to eliminate one genome, that is, one-third of the genotype. An attempt was made to do this by producing pentaploids (2n- 5x=35), AABBD, involving 9 standard varieties of T. aestivum (Chinese Spring, Peko, Koga, Svenno, C 591, A.T. 38, April Bearded, C 518 and H- 23-42) with 9 tetraploid (2« 4x=28), AABB, varieties of Triticum (Carleton, Mechmudy, Iumillo, Nursi, Samra, Kubankum, T1, 2D 1 and 33 D 1) in a number of combinations. Chinese Spring disomic was the most successful hexaploid parent giving a seed set of 22.5% which was more than 3 times than that found with any other hexaploid parent (1 to 7%). Crosses of the tetraploid variety Machmudy with Chinese Spring disomic produced highest (48 %) seed set. No seed was obtained by crossing a synthetic tetraploid, Triticum monococcum x Aegilops speltoides with varieties (Chinese Spring disomic, Koga and A.T. 38) of T. aestivum.

STUDIES ON RADIATION-INDUCED MUTATIONS IN SOME VARIETIES OF RICE
ABSTRACT:
Dry seeds of two standard local varieties of rice namely, Dokri Basmati and Jajai-11 were subjected to different dosages of gamma-rays and fast neutron. Data on the seed fertility of the M\ generation plants indicated that

STUDIES ON THE CEPHALIOPHORA IRREGULARIS THAX.
ABSTRACT:
Cephaliophora irregularis Thax. is reported for the first time in Pakistan. From the cultural studies of C. irregularis it was noticed that the cardinal temperatures for growth are 20, 30, 35 and 40 C. The sporulation was abundant only on DA between 25 and 40 C. Maximum growth and sporulation was at 6.1-7.5 pH range while on MEA the sporulation was at pH 9.1 only.

ACID PHOSPHATASE IN TARAXACUM ROOTS
ABSTRACT:
The enzyme acid phosphatase was studied in Taraxacum roots with respect to its substrate and pH specificity. A pH optima of ca. 4.8 was noted after using ten different phosphate compounds as its substrate. It was found that this enzyme is actively hydrolyzing not only the sugar phosphates but also the nucleotides and coenzymes, releasing free inorganic phosphates, though the rate of the reaction differs with different

ANATOMICAL EFFECTS OP INDOLEBUTYRIC ACID ON PEDICEL ABSCISSION OF CORCHORUS
ABSTRACT:
Abscission of pedicel of Corchorus trilocularis after its pollination with C. olitorius is completely suppressed by the application of IB A (300 PPM) around the pedicel of the pollinated flower. Longisections of the pedicels oj self-pollinated flowers, when compared with those of the treated ones showed no difference in the shape and size of their cells in the abscission zone. In the crosses without IBA abscission zone was found to be differentiated 42 hrs after pollination by the concurrent occurrence of cell division and initiation of lysis.

STUDIES OF ROOT DISTRIBUTION AND ROOT ANATOMY OF PASPALUM DISTICHUM L.
ABSTRACT:
Paspalum distichum L. is a perennial grass species which grows in water ditches or in badly water-logged soils along water courses in the West Pakistan plains. The root system of this species has been described. Reported here are the results obtained from the studies of (i) the distribution of the roots in the soil in the field, and (ii) the amount of intercellular spaces present in the cortex of the roots as they are growing at different depths in the soil. P. distichum should be regarded if not a shallow-rooting species, at least one which is intermediate between shallow- rooting and deep-rooting species. The intercellular spaces in the cortex of the old cord root have been found to increase with an increase in soil depth. The presence of these spaces should be considered as an adaptation for growth in poorly aerated media.

HYBRIDIZATION IN ACACIA NILOTIC A COMPLEX Short Communication A STUDY OF MICROBIAL FLORA OF DADHI
ABSTRACT:
Morphological studies of the members of Acacia nilotica complex indicate that the vast amount of variability encountered in this group is because of hybridization between A. nilotica ssp. indica and A. nilotica ssp. hemis- pherica. This hybrid population may backcross either with the first or the second parent producing ssp. adansonii and ssp. subalata type plants respec- tively. Human influence in creating disturbed habitat seems to be the most important factor in the promotion of hybridization. ‘Dadhi’ or ‘dahi’ is a form of fermented milk product. Its quality greatly depends on the microbial flora present in it. We undertook the present work to find out the micro-organisms present in the good ‘dadhi’ and those responsible for the formation of defective ‘dadhi’ under our local conditions.

A STUDY OF MICROBIAL FLORA OF DADHI
ABSTRACT:
Dadhi’ or ‘dahi’ is a form of fermented milk product. Its quality greatly depends on the microbial flora present in it. We undertook the present work to find out the micro-organisms present in the good ‘dadhi’ and those responsible for the formation of defective ‘dadhi’ under our local conditions.

A CONTRIBUTION TO THE TAXONOMY OF THE GENUS SESBANIA ADANSON FROM WEST PAKISTAN
ABSTRACT:
The taxonomy, nomenclatural position and distribution of the genus Sesbania from West Pakistan has been discussed. Four species namely, S. grandiflora (L.) Poir, S. sesban (L.) Merrill, S. bispinosa (Jccq.) Wight and S. concolor Gillett are recognised from the area under consideration. Four varieties have been recognised under S. sesban viz. var. sesban, var. bicolor, var. concolor and var. muricata including a new variety (muricata

EXTRACTION OF ANCESTRAL CONSTITUENTS OF NATURAL POLYPLOIDS. II. STUDY OF THE FIRST BACKCROSS OF THE PENTAPLOIDS (AABBD) AND 34- CHROMOSOME PLANTS TO THE HEXAPLOID TRITICUM AESTIVUM (AABBDD)
ABSTRACT:
For the extraction of tetraploid component of a hexaploid the production and hackcrossing of fertile pentaploids is essential. The first hackcross of the F\ pentaploids to varieties Chinese Spring, Peko, Koga, Svenno and A. T. 38 o/Triticum aestivum were made. When the hexaploids were used as pollen parent, the total seed set was 16 %; in the reciprocal direction it was 3 %. There were differences in the crossability of different monosomic lines used and in the survival and sterility of the penta- ploids and 34-chromosome plants recovered from the first back cross.

GENETICS OF RUST RESISTANCE IN TETRAPLOID WHEATS. IV. GENETICS OF LEAF RUST RESISTANCE IN TWO DURUM WHEATS
ABSTRACT:
The inheritance of resistance in C.I. 7809 and P.I. 109593 to leaf rust of wheat, Puccinia recondita tritici was studied. It was found that resistance in C.I. 7809 to strain 135Z) was conditioned by a dominant gene Lrt\ and two recessive genes Irti and Irty. The gene Lrt\ was epistatic to both the genes Lrt2 and Lrt The resistance to strain 68C was conditioned by gene Lrt\ and to strain 64/f by genes Lrt \ and lrt2. The physiologic resistance seemed to operate throughout the life of wheat plant. The resistance in P.I. 109593 to strains 1 35 D and 64A was found to be controlled by two recessive genes lrt4 and lrt5. It was further observed that these genes were different and independent of genes Lrt\, lrt2 and lrt3