in order to study of combining ability and heterosis in cotton (gossypium hirsutum l.), six hopeful genotypes were crossed in a half-diallel scheme at gonbad research station. fifteen f1 hybrids along with six parents were grown in randomized complete block design with 3 replications, in 2004. combining ability estimates were calculated according to method 2, model 1 of griffing (1956a,b). rela...

In this work, the analysis of a tree-inspired fractal structure is presented. First, trajectories of points on branches of different hierarchy of a tree that oscillates freely are recorded in experiments. Then, the principle axes and ellipses of displacements are determined analytically for a sympodial fractal mechanical model. Modes of oscillations and their frequencies are found numerically f...

Variation in the branching of plant inflorescences determines flower number and, consequently, reproductive success and crop yield. Nightshade (Solanaceae) species are models for a widespread, yet poorly understood, program of eudicot growth, where short side branches are initiated upon floral termination. This "sympodial" program produces the few-flowered tomato inflorescence, but the classica...

BACKGROUND Asexual increase occurs in virtually all colonial organisms. However, little is known about the intrinsic mechanisms that control asexual reproduction and the resultant morphologies of colonies. Scleractinian corals, both symbiotic (zoaxanthellate) and non-symbiotic (azooxanthellate) corals are known to form elaborate colonies. To better understand the growth mechanisms that control ...

The transition from vegetative to floral meristems in higher plants is programmed by the coincidence of internal and environmental signals. Classic grafting experiments have shown that leaves, in response to changing photoperiods, emit systemic signals, dubbed 'florigen', which induce flowering at the shoot apex. The florigen paradigm was conceived in photoperiod-sensitive plants: nevertheless ...

BACKGROUND AND AIMS The leaf rosettes of the carnivorous Pinguicula moranensis follow a spiral phyllotaxis approaching a Fibonacci pattern while the stalked flowers arise from extra-axillary sites between the leaves. The organization of this rosette has been discussed by various authors, with various results. The aim of the present study was to clarify the development of the flowering rosettes ...

introduction salinity is a major abiotic stress that affects approximately 7% of the world’s total land area. cotton (gossypium barbadense l.) is considered as one of the most important cash crops which is widely used for agricultural and industrial purposes. although, cotton is classified as one of the most salt-tolerant major crops but its growth and development are adversely affected by soil...