How could I make this diagram with TikZ (LaTeX2e) ((split lines))

Question

I would like to create a similar figure in TikZ:

(The size of the nodes is not on purpose and I tried to make all rectangles' corners rounded)

This is my code so far (MWE):

\documentclass{article}

\usepackage{mwe}
\usepackage{tikz}
    \usetikzlibrary{positioning,shapes.misc}
    \tikzstyle{rblock} = [rounded rectangle, draw, text width=1.4cm, text centered, minimum height=4em]

\begin{document}

\blindtext

\begin{center}
\begin{tikzpicture}[auto,node distance=2cm,transform shape,scale=0.8]
\node [rblock] (wibble) {wibble};
\coordinate [below=1cm of wibble] (c1);
\node [rblock,left=3cm of c1] (wobble) {wobble};
\node [rblock,right=3cm of c1] (wubble) {wubble};
\coordinate [below=1cm of wobble] (c2);
\node [rblock,left=0.2cm of c2] (foo) {foo};
\node [rblock,right=0.2cm of c2] (bar) {bar};
\node [rblock,below=0.3cm of wubble] (qux) {qux};
\node [rblock,left=0.2cm of qux] (baz) {baz};
\node [rblock,right=0.2cm of qux] (quux) {quux};
% TODO lines
\end{tikzpicture}
\end{center}

\end{document}

This gives:

I was trying to find a solution myself, but I don't even know where to start. I tried looking for 'split arrow' but it didn't help. Could you please help me out?

So how could I get these lines between the nodes?

Also, how could I make the rectangles more like the ones on my lame drawing? So I would like the corners to be rounded, but not as much as they are with rounded rectangle in the shapes.misc TikZ library...

Answer 1

forest package and its edges library could be an option:

\documentclass{article}

\usepackage{mwe}
\usepackage{forest}
\useforestlibrary{edges}

\begin{document}

\blindtext

\begin{center}
\begin{forest}
for tree={draw, rounded corners, minimum width=2cm, minimum height=4em},
forked edges,
[wibble
    [Wobble
        [Foo]
        [Bar]]
    [Wubble
        [Baz]
        [Qux]
        [Quux]]]
\end{forest}
\end{center}

\end{document}